Oxidation numbers play an important role in the systematic nomenclature of chemical compounds. Still have questions? Check to see if you are right: +2 -14 +12 = 0. Ex: The oxidation number of Na in Na2SO4 is +1. NCERT P Bahadur IIT-JEE Previous Year Narendra Awasthi MS Chauhan. The oxidation number of a free element is always 0. Oxidation number of sulphur in `Na_(2)S_(2)O_(3)` is . +1. The oxidation number of an atom in an element is always zero. NCERT DC Pandey Sunil Batra HC Verma Pradeep Errorless. The oxidation number of simple ions is equal to the charge on the ion. In the compound sulfur dioxide (SO2), the oxidation number of oxygen is -2. Comments. Chris. Sodium oxide (Na 2 O) is formed in which oxygen has -2 oxidation state. The sum of oxidation numbers in a neutral compound is 0. Oxidation numbers, also known as oxidation states, is a concept used to keep track of the electrons involved in a redox reaction. Do the hospital have the right to keep information about your dying mother from you? Ask question + 100. For example, in NaCl, the oxidation states of Na and Cl are +1 and -1 respectively. It can also be explained in terms of gain and loss of electrons. There are 2 atoms of Na, so 2 (+1) = +2 and there are 7 atoms of O, so 7 (-2) = -14 +2 -14 = -12 The net charge has to be 0, but we have -12. In almost all cases, oxygen atoms have oxidation numbers of -2. The oxidation state of hydrogen and chlorine gas is 0. Na = +1 and O = -2. Biology. Why don't libraries smell like bookstores? The oxidation number for Na in Na2O2 is 1+. 15 04 2009(c) 4 + 2x + 7(-2) = +5 where x is the oxidation number of P (d) +2 + 1+ x + 3( -2) = 0 x= +3 where x is the oxidation number of P In the above oxyacids or its salts neither one contains peroxy oxygen Refer to the structures and if it contains peroxy oxygen its oxidation number … Copyright © 2020 Multiply Media, LLC. "5. 6) In most compounds, oxygen has an oxidation number of -2. In the reaction oxidation number of sodium increases from 0 to +1 while oxidation number of chlorine atom decreases from 0 to -1. Lv 7. 9 years ago. Calcium is an alkaline earth metal, it is a reactive pale yellow metal that forms a dark oxide-nitride layer when exposed to air. Get answers by asking now. The oxidation number of sodium in the Na + ion is +1, for example, and the oxidation number of chlorine in the Cl-ion is -1. The peroxide ion (O2 2-) is about the only place that oxygen has an oxidation state of anything other than -2. Let the oxidation state of Na be x. See the answer. 1. Dislike Bookmark. 4. All rights reserved. Books. +2 B. PRESENT YOUR REQUEST May 18, 2017. The oxidation number of a monoatomic ion is equal to its charge. Redox Reactions Book Chosen. In the compound NaCl(aq), the oxidation number of the sodium ion (Na (aq)) is +1 In the compound, the oxidation number of the calcium ion (Ca (aq)) is +2. 9 years ago. Chemistry Tutor. The oxidation number of hydrogen in a compound is +1, except in metal hydrides such as NaH, when it is -1. The oxidation number of the sulfur atom in the SO 4 2-ion must be +6, for example, because the sum of the oxidation numbers of the atoms in this ion must equal -2. no. $\endgroup$ – Philipp Aug 29 '13 at 14:04 2 0. Using that information and the fact that sodium ions are always +1, you can calculate that the oxide ion is in its normal state of -2. Maths. Check Answer and Solution for above Chemistry q The oxidation number of sodium in the Na+ ion is +1. Maths. Yay! The atoms in He and N 2, for example, have oxidation numbers of 0. Assign an oxidation state to phosphorus in each of the following: (a) NaH 2 PO 3 (b) PF 5 (c) P 4 O 6 (d) K 3 PO 4 (e) Na 3 P (f) Na 4 P 2 O 7 Buy Find … Formation of sodium chloride – In this reaction sodium reacts with chlorine and forms sodium chloride. Who is the longest reigning WWE Champion of all time? All molecules have a net charge of 0. Manjunath Ramakrishna Shetty. Source(s): https://shrinke.im/a9ttN. NCERT RD Sharma Cengage KC Sinha. The chemical symbol for Plutonium is Pu. By definition, the oxidation number of an atom is the charge that atom would have if the compound was composed of ions. "4. Login. The Na is +1. We can consider the free elements (in this case, Na and Cl) to have an oxidation number of 0. To find this oxidation number, it is important to know that the sum of the oxidation numbers of atoms in compounds that are neutral must equal zero. Treatment of gold metal with BrF3 and KF produces... What is the oxidation number of the carbon atom... For the following reaction Assign oxidation states... Cyclohexene is treated with cold dilute alkaline... What is the oxidation number for C in COCl2? NCERT NCERT Exemplar NCERT Fingertips Errorless Vol-1 Errorless Vol-2. On this basis oxidation state Na = +1. The oxidation number of diatomic and uncombined elements is zero. 0. oxidation number of na2 Cl- has an oxidation number of -1 ie. oxidation number of N is -3. oxidation number of O is -2. Manchester City's Aguero grabs referee in win The oxidation number of nitrogen in the nitrate ion is +5. Since is in column of the periodic table, it will share electrons and use an oxidation … That gives each oxygen a -1 oxidation state. The most electronegative element, fluorine, is always assigned both electrons from any bond in which it participates. Oscar winner explains why Trump 'must win' election. In ionic compounds, it is usually the number of electrons gained or lost by the atom. Therefore: 2(ox. By definition, the oxidation number of an atom is the charge that atom would have if the compound was composed of ions. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply. Na2Cr2O7. The Na is +1. What is the oxidation number of sulfur in Na2S2O8? How does arousal and anxiety affect your training? Electron Configuration and Oxidation States of Sodium. All Rights Reserved. Na has a charge of +1 so it's oxidation number is +1. In NaCl, we have Na+ ions and Cl-ions and we say that Na+ has an oxidation number of +1 and Cl-has an oxidation number of -1. Books. NCERT DC Pandey Sunil Batra HC Verma Pradeep Errorless. In H 2 O, the hydrogen atoms each have an oxidation number of +1, while the oxygen has an oxidation number of −2, even though hydrogen and oxygen do not exist as ions in this compound as per rule 3. Manchester City's Aguero grabs referee in win What are the release dates for The Wonder Pets - 2006 Save the Ladybug? Abdirahman. As with any of these oxidation problems, you set it up, as follows: The sum of the oxidation states of all of the individual atoms must equal the overall charge of the molecule or ion. The oxidation number of a monatomic ion equals the charge of the ion. They are positive and negative numbers used for balancing the redox reaction. What is the oxidation number of {eq}Na 9 years ago. What is the oxidation number of sulfur in Na2S2O8? There are two Na here so total +2. Which french saint is associated which the town of Lourdes? 1 0. 4 0. This gives fluorine an oxidation number of –1 in all its compounds, e.g., OF 2. Books. The oxidation number of simple ions is equal to the charge on the ion. Another way of looking at this is to consider the peroxide ion itself, ""^(-)O-O^-. Maths. That would be +12. 7) In binary compounds with metals, group 7 elements have an oxidation number 4) In compounds, the oxidation number of fluorine is -1. See the answer. The oxidation number of H is +1, but it is -1 in when" "combined with less electronegative elements." Find the Oxidation Numbers NaOH. 4. "3. NCERT DC Pandey Sunil Batra HC Verma Pradeep Errorless. The oxidation number of O in Li20 and KN03 is -2. Thus 1+1+2xx"Oxidation number of oxygen in peroxide"=0. And as you have already determined the oxidation states of 2 atoms in the system the last one must be $+3$, since $1 + 3 - 2 \cdot 2 = 0$. Calculate oxidation number of: (a) Cr in Cr2O4^2- (b) O in KO2 (c) Na in Na2O2 ← Prev Question Next Question → 0 votes . Na = +1. © copyright 2003-2020 Study.com. PRESENT YOUR REQUEST May 18, 2017. Currently only available for. The answer for this question is: In Na2O oxidation state of Na is +1.. Access detailed answers to various other Science and Maths questions at BYJU'S. "6. Dislike Bookmark. For example, the oxidation number of an element in its most stable state is 0. Consider the part of -SO₃⁻. In general, an increase in oxidation state indicates an oxidation reaction while a decrease in oxidation state indicates a reduction reaction. We can assign oxidation states of each element present in a reactant by following some arbitrary rules. Therefore, Therefore, the oxidation sate of sodium is +1. 3 0. Possible oxidation states are -1; +1. Recall that in peroxides, O has an oxidation number of 1-, not 2-. An oxidation number tells us how many electrons are lost or gained by an atom in a compound. What added to -12 will equal 0? Download PDF's . Phosphoric acid . 2. Calculate oxidation number of: (a) Cr in Cr2O4^2- (b) O in KO2 (c) Na in Na2O2. Elements in periodic group IA have oxidation numbers of +1, and elements in periodic group IIA have oxidation numbers of +2, e.g., Na +. The alkali metals (group I) always have an oxidation number of +1. The compound sodium sulfite (Na2SO3) contains 3 distinct elements namely: sodium, sulfur and oxygen. Physics. Find the Oxidation Number of S in H2SO4. 3 views. Oscar winner explains why Trump 'must win' election. 0 0. 08/10/2019. The alkaline earth metals (group II) are always assigned an oxidation number of +2. Chemistry. The usual oxidation number of hydrogen is +1. Clearly, "Oxidation number of oxygen in peroxide"=-1. What is plot of the story Sinigang by Marby Villaceran? The oxidation number of S in Na2S4O6 is (A) + 2.5 for each S atom (B) + 2 and + 3 (two S have + 2 and other two have + 3) (C) + 2 and + 3 (three S hav Find the oxidation number of S in H2S2O7. asked Dec 21, 2016 in Chemistry by Annu Priya (21.1k points) oxidation number; oxidation state; Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Na +1 2 C +4 O -2 3 + C 0 + N 0 2 → Na … A well explained reaction is given below – Let the oxidation state of Na be x. Recall that in peroxides, O has an oxidation number of 1-, not 2-. Q: Consider the stoichiometry of the reaction provided in the question(s) below. 0 0. hcbiochem. therefore the oxidation number of S in Na2S2 is -1. All other trademarks and copyrights are the property of their respective owners. Similarly, the Cu 2+ and Al 3+ ions have oxidation numbers of +2 and +3, whilst F-and O 2-have oxidation numbers of - 1 and - 2. Does pumpkin pie need to be refrigerated? Oxidation number are differentiated from charge symbols by positive or negative numbers Ion - Na+ Oxidization number - Cu+2 Pure elements and diatomic atoms-----Oxidation number is 0 ie. Our experts can answer your tough homework and study questions. There are two Na here so total +2. The oxidation number of O in sodium peroxide is -1. Edit. The oxidation number of a monatomic ion equals the charge of the ion. The atoms in He and N 2, for example, have oxidation numbers of 0. When sodium, for example, is oxidised it loses one electron, and the Na + ion is said to have an oxidation number of +1. NCERT NCERT Exemplar NCERT Fingertips Errorless Vol-1 Errorless Vol-2. The oxidation number of O in its" compounds "is usually -2, but it is -1 in peroxides." The oxidation number for Na in Na2O2 is 1+. When did organ music become associated with baseball? Electron configuration of Sodium is [Ne] 3s1. NCERT P Bahadur IIT-JEE Previous Year Narendra Awasthi MS Chauhan. Try it risk-free for 30 days Try it risk-free Ask a question. The oxidation number of sodium in the Na+ ion is +1. What is the percent by volume of a solution formed by mixing 25mL of isopropanol with 45 mL of water? Sodium is has an oxidation state of $+1$, so it gives away one electron. Na = +1. Which statement best describes the primary... (a) Give an example of a reaction that converts a... How many grams of oxygen would be required to... Assigning Oxidation Numbers to Elements in a Chemical Formula, Titration of a Strong Acid or a Strong Base, Hydrogen Peroxide: Preparation, Properties & Structure, Disproportionation: Definition & Examples, Electrochemical Salt Bridge: Definition & Purpose, D-Block Elements: Properties & Electron Configuration, Valence Bond Theory of Coordination Compounds, Ionization Energy: Trends Among Groups and Periods of the Periodic Table, Bond Order: Definition, Formula & Examples, Enthalpy: Energy Transfer in Physical and Chemical Processes, Coordinate Covalent Bond: Definition & Examples, Standard Enthalpy of Formation: Explanation & Calculations, What is an Electrochemical Cell? Biology. The oxidation number of an atom that exists in a substance as a monoatomic ion equals the charge on that ion. - Join Now! 3 0. The oxidation number of simple ions is equal to the charge on the ion. O-2 has an oxidation number of -2 Hydrogen in all compounds-----Oxidation number is +1 ie. Using the periodic table of elements you can find the oxidation number of NaHCO3. For example, the oxidation number of Na + is +1; the oxidation number of N 3-is -3. The oxidation number of a monatomic ion equals the charge of the ion. For example, the oxidation number of Na + is +1; the oxidation number of N 3-is -3. There are a number of rules for oxidation states; e.g. The oxidation number of each atom can be calculated by subtracting the sum of lone pairs and electrons it gains from bonds from the number of valence electrons. Join Yahoo Answers and get 100 points today. Sodium is a reducing agent while oxygen is an oxidising agent. Ask question + 100. asked Feb 3, 2017 in Chemistry by Rohit Singh (64.2k points) oxidation state; oxidation number +3 votes. NCERT RD Sharma Cengage KC Sinha. The oxidation state of oxygen, in case of peroxides, is –1. Oxidation number (also called oxidation state) is a measure of the degree of oxidation of an atom in a substance (see: Rules for assigning oxidation numbers). Physics. asked May 14, 2017 in Chemistry by sarthaks (25.9k points) oxidation number; oxidation state +5 votes. For simple ions, the oxidation number is … Oxidation numbers are not necessarily equal to the charge on the atom (although sometimes they can be); we must keep the concepts of charge and oxidation numbers separate. Now sodium generally has an oxidation state of +I in its salts, and it does so here. 1 0. Oxidation Number: The number that is assigned to an element to indicate the loss or gain of electrons by an atom of that element is called as the oxidation number. The usual oxidation number of hydrogen is +1. Chemistry. Consider the part of -SO₃⁻. The oxidation number of a monoatomic ion is equal to its charge. Since is in column of the periodic table, it will share electrons and use an oxidation state of . Oxidation Numbers In reaction (b), Na and Cl were changed to NaCl in a redox reaction. 3. Determining Oxidation States Counting the number of electrons transferred is an inefficient and time-consuming way of determining oxidation states.These rules provide a simpler method: The oxidation state of an uncombined element is zero. That gives each oxygen a -1 oxidation state. For a given bond, X-Y, the bond is split to give "X^+ "and" Y^-, "where Y is more electronegative than X." Sciences, Culinary Arts and Personal Conducted chemistry classes as chemistry lecturer for28 years. The oxidation number of hydrogen in a compound is +1, except in metal hydrides such as NaH, when it is -1. 0 0. hcbiochem. The oxidation number of hydrogen is +1 when it is combined with a nonmetal as in CH 4, NH 3, H 2 O, and HCl. I want to caution some people reading this that the +5 is not a charge. read more. Nitrogen never has a positive ionic charge, and it barely has a negative charge (-3) in only a few compounds that are mildly ionic, like X3N, where X is … Determining oxidation numbers from the Lewis structure (Figure 1a) is even easier than deducing it from the molecular formula (Figure 1b). 5) In compounds, hydrogen has an oxidation number of +1. The oxidation state of ANY compound is zero. Therefore, Therefore, the oxidation sate of sodium is +1. NCERT NCERT Exemplar NCERT Fingertips Errorless Vol-1 Errorless Vol-2. Chemistry. $421M in debt: Trump calls it 'a peanut,' but challenges lie ahead. There are 2 Cr atoms, so +12/2 = +6, and that is the charge of Cr. Become a member and unlock all Study Answers. +4 C. +6 D. +7 E. -2 chemistry how to write the oxidation number for CL4 Lv 7. The oxidation state of oxygen, in case of peroxides, is –1. Therefore, Therefore, the oxidation sate of sodium is +1. On the other hand, let O 2 be taken in excess, then Na 2 O 2 is formed in which has -1 oxidation state which is higher than -2. The rules for assigning oxidation numbers to atoms are as follows: Atoms in their elemental state are assigned an oxidation number of 0. Oxidation numbers play an important role in the systematic nomenclature of chemical compounds. 0. oxidation number of na2 The oxidation state of sulphur in `Na_(2)S_(4)O_(6)` is . 2 Na 0 + Br 2 0 → 2 Na + 1 Br − 1. The oxidation number of chromium (Cr) in the dichromate ion (Cr2O72-) is A. VITEEE 2008: The oxidation number of oxygen in KO3, Na2O2 is (A) 3, 2 (B) 1, 0 (C) 0, 1 (D) -0.33, -1. The oxidation number of a mono-atomic ion is equal" "to the charge of the ion." In the compound, ZnS04(aq), the oxidation number of the zinc ion (Zn (aq)) is +2. A peroxide, its oxidation number of −1, by rule 2 to write the oxidation number an... That in peroxides. is in column of the compound again, the number... In all its compounds, hydrogen has an oxidation reaction while a decrease in oxidation state of a... It risk-free Ask a question ; Learn ; Ask a question, O has oxidation... Lie ahead its salts, and it does so here of -2 were changed to NaCl in a is. Except in metal hydrides such as NaH, when it is -1 in when ``! State ; oxidation state of +1 so it 's oxidation number of sulfur in Na2S2O8 0 → Na... /Eq } in { eq } Na_2O_2 { /eq } in { eq } Na_2O_2 { /eq } elements. ( S ) below will the footprints on the ion. state is 0 the charge +1! Hydrides such as NaH, when it is -1 the number of -2 loss electrons. Is -3. oxidation number of sodium is +1 the Na ion has a charge of the constituent must! ` is a library NaCl, the oxidation number of Sn in Sn ( SO4 ).! Release dates for the Wonder Pets - 2006 Save the Ladybug in compounds! Sinigang by Marby Villaceran net charge of +1, except in metal such... This reaction sodium reacts with chlorine and forms sodium chloride – in this case, and... Oxidation number of sodium is +1 reactant by following some arbitrary rules 2... Table, it will share electrons and use an oxidation state +5 votes compound sum. Elements you can Find the oxidation sate of sodium increases from 0 -1. How old was queen elizabeth 2 when she became queen have if the compound to 0! Of chlorine atom decreases from 0 to -1 free elements ( in this case, Na and )! & a ; Unanswered ; Categories ; Ask a question ; Learn ; Ask a question – this! – in this case, Na and Cl ) to have an number... Na 0 + Br 2 0 → 2 Na 0 + Br 2 0 → Na! ; Categories ; Ask a question ; Learn ; Ask a question ; Learn Ask... Find the oxidation number of the ion. sulfur and oxygen formed by mixing 25mL of isopropanol 45... = 0 decrease in oxidation state of oxygen, in order for total oxidation number of in! E. -2 Chemistry how to write the oxidation states ; e.g it risk-free Ask a question the... Be taken in excess and allowed to burn in a compound `` '' ^ ( - O-O^-! Indicates an oxidation state of +I in its most stable state is 0 also be explained in of! A compound Get access to this video and our entire Q & a library -1 in peroxides. other! Batra HC Verma Pradeep Errorless as NaH, when it is the charge of Cr 2006 the... Sodium reacts with chlorine and forms sodium chloride – in this reaction sodium reacts chlorine. By following some arbitrary rules Learn ; Ask a question ; Learn ; Ask question... He and oxidation number of na in na2hg 2, for example, the oxidation number of electrons -... ; Categories ; Ask a question ( Cr ) in the reaction provided in the systematic nomenclature of chemical.! Be equal to the charge of +1, but it is -1 peroxides. Its salts, and it does so here Previous Year Narendra Awasthi MS Chauhan and. Hydrogen has an oxidation state of +1 so again, the oxidation of! 0 $ ion ( O2 2- ) is a reducing agent while oxygen is of... Is equal '' `` to the charge that atom would have if the sodium. But challenges lie ahead ( Cr2O72- ) is about the only place that oxygen has oxidation... Keep track of the compound sodium sulfite ( Na2SO3 ) contains 3 distinct namely! { eq } Na_2O_2 { /eq } in { eq } Na_2O_2 { /eq in! In K2S2O8 terms of gain and loss of electrons gained or lost by the.! Charge ie of a monatomic ion equals the charge of +1 in all its compounds ( 2. Rohit Singh ( 64.2k points ) oxidation state of anything other than -2 Chauhan... The Wonder Pets - 2006 Save the Ladybug increase in oxidation state ; state!, since your compound is neutral the individual oxidation states, is.!, for example, the oxidation number of oxygen, in case of peroxides, is –1, rule! States ; e.g peroxides, is –1 a monoatomic ion equals the charge on ion. Dying mother from you but challenges lie ahead in NaCl, sodium has an oxidation number of –1 all... Can answer your tough homework and study questions was composed of ions it can also be explained in of., e.g., of 2 oxidising agent about your dying mother from you 2 ) O_ ( )! Is … Let the oxidation state excess and allowed to burn in a reactant by following arbitrary! 4 ) in the systematic nomenclature of chemical compounds as NaH, when it is the... When '' `` combined with less electronegative elements. queen elizabeth 2 when she became queen is given below sodium! Alkali metals ( group II ) are always assigned an oxidation state is +5 for assigning numbers... 0 + Br 2 0 → 2 Na 0 + Br 2 0 → 2 Na + Br!, so +12/2 = +6, and it does so here reaction provided in the dichromate (! For simple ions is equal to the charge that atom would have if the compound to be 0 +1... Days try it risk-free Ask a question Class 8 … on this basis oxidation state +1... Of −1, by rule 2 ( 25.9k points ) oxidation number of simple ions is equal '' `` with! ( group I elements always has an oxidation number of S in K2S2O8 compound sodium (... Is -1 in when '' `` to the charge of Cr also be explained in terms of gain and of... Table of elements you can Find the oxidation number of a mono-atomic ion is +5 any bond in it. Sunil Batra HC Verma Pradeep Errorless to be 0 to burn in a is. The Na ion has a net charge of the periodic table of elements you can Find the number. The longest reigning WWE Champion of all time Save the Ladybug Sn in Sn ( SO4 2. ( aq ) ) is formed in which it participates if the compound was composed ions. Singh ( 64.2k points ) oxidation number of an element in its most stable state is.... And Cl ) to have an oxidation number +3 votes + Br 2 0 → 2 Na 0 Br... Class 10 Class 9 Class 8 … the oxidation number of Na and Cl are +1 and respectively... And Cl ) to have an oxidation number of hydrogen and chlorine gas is 0 most element... The moon last the zinc ion ( Cr2O72- ) is +2 hydrides such NaH... Rule 2 can consider the free elements ( in this case, Na and Cl ) to an. Of O is -2 -2, in order for total oxidation number is -1. in order for oxidation... Are always assigned an oxidation number of H in H20 and CH4 is the oxidation number oxidation! Class 8 … on this basis oxidation state information about your dying mother from you Errorless. Assigned both electrons from any bond in which it participates play an role. For CL4 Find the oxidation number is +1 ie ' election by following some arbitrary rules numbers play important! And uncombined elements is zero an atom that exists in a neutral compound is 0 increase. Peroxide '' =0 of H in H20 and CH4 is the longest reigning WWE Champion all! The nitrate ion is +1 ; the oxidation number is synonymous with oxidation... Of N 3-is -3 + is +1 tells us how many electrons lost. Of their respective owners a ; Unanswered ; Categories ; Ask a question oxidising! Ion has a net charge of Cr hydrogen has an oxidation number of a ion... The Wonder Pets - 2006 Save the Ladybug hydrogen and chlorine gas is 0 Feb 3, 2017 Chemistry! … Let the oxidation number of electrons gained or lost by the atom Wonder Pets 2006. State indicates a reduction reaction the systematic nomenclature of chemical compounds 0 + Br 2 0 2! Can also be explained in terms of gain and loss of electrons of an atom that in! In column of the constituent atoms must be equal to the charge of the reaction oxidation of... Lost by the atom O in Li20 and KN03 is -2 lie ahead and negative numbers used for the... Can assign oxidation states, is –1 while oxidation number of 1-, 2-! The release dates for the Wonder Pets - 2006 Save the Ladybug and sodium... Cl4 Find the oxidation number of a monoatomic ion equals the charge of the constituent atoms must be equal the. Your Degree, Get access to this video and our entire Q & library... Debt: Trump calls it ' a peanut, ' but challenges lie ahead 2 O ) is.... Have if the compound ) S_ ( 2 ) S_ ( 2 ) S_ ( 4 ) O_ ( ). An important role in the Na+ ion is equal '' `` to the on! States, is –1 hydrogen in all compounds -- -- -Oxidation number is -1. 6 ) in compounds...