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# Valence electrons & electronic charge on elements & molecule

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1. State the number of valence electrons for a hydrogen atom and a chlorine atom.

2. State the number of valence electrons for a hydrogen atom and a chlorine atom in a covalent bond.
Use the periodic table to predict an ionic charge for each of the following metal ions.

3. Be ion

4. Cs ion

5. Ga ion

6. Pb ion
Use the periodic table to predict the ionic charge for each of the following nonmetal ions.

7. I ion

8. S ion

9. Se ion

10. P ion
Write out the electron configuration for each of the following nonmetal ions.

11. Br -

12. O2-

13. Se2-

14. N 3-

15. What is the general trend in electronegativity across a series in the periodic table?

16. Which elements are more electronegative, semimetals of nonmetals?
State whether the representative particle in each of the following substances is an atom, a molecule, or a formula unit.

17. plutonium, Pu

18. ozone, O3

19. plutonium(III) oxide. Pu2O3

20. Explain why the radius of a chloride ion (0.181 nm) is about twice that of chlorine atom (0.099 m).

https://brainmass.com/physics/conduction/valence-electrons-electronic-charge-on-elements-molecule-123446

#### Solution Preview

1. State the number of valence electrons for a hydrogen atom and a chlorine atom.
Valency, in chemistry is the combining capacity of an atom expressed as the number of single bonds the atom can form or the number of electrons an element gives up or accepts when reacting to form a compound. The valence of an atom is determined by the number of electrons in the outermost, or valence, shell.
The atomic number of Hydrogen is 1: Electronic configuration is 1s1. Valence electron of hydrogen atom is 1.
The atomic number of chlorine is 17: Electronic configuration is 1s2 2s2 2p6 3s2 3p5. Therefore, the number of valence electrons in chlorine atom is 7.

2. State the number of valence electrons for a hydrogen atom and a chlorine atom in a covalent bond.
The valence electrons of hydrogen and chlorine atom is 1. HCl is formed when 1 pair of valence electrons is shared, one from the hydrogen atom and one from the chlorine atom.
Use the periodic table to predict an ionic charge for each of the following metal ions.
The charge an element gains on reacting with other elements depends on the number of valence electrons of that element. Metals, which commonly donate electrons and form compounds in which they exist in the positive, or cationic, state, are assigned positive oxidation numbers. Nonmetals, which commonly accept electrons and in compounds exist in the negative, or anionic, state, are assigned negative oxidation numbers.

3. Be ion
Atomic no.: 4; Belongs to periodic group IIA; 2 e- in outermost shell (2s2), therefore the Be ion will be positively charged as it can easily donate electrons. Be+2

4. Cs ...

#### Solution Summary

This solution has answers to the questions based on valence electrons, valency, electronic configuration and charge on elements, metals, nonmetals, semi metals and molecules.

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