Understanding Key Ideas2. Proton and neutron3. Neutron6. a. +10 b. the number of positive charges in the nucleus is 10 (10 protons) There are no electrons in the nucleus.

Element Atomic Number Number of protons

Number of electrons

A Pb 82 82 82B O 8 8 8C Zn 30 30 30D Fe 26 26 26E Ag 47 47 47F Cl 17 17 17

10. (a) Electron(b) Proton, electron(c) Electron(d) Neutron(e) Proton, neutron(f) Proton11. In a covalent compound, atoms bond togetherby sharing a pair of electrons. In an ionic compound,ions form as a result of the transfer ofelectrons, and then ions of opposite chargeattract each other.12. (a) Bohr and Lewis diagrams are similar inthat they show the valence electrons andhow they result in bond formation.(b) They are different in that Bohr diagramsshow all the atoms in each atom or ion,while Lewis diagrams show only valenceelectrons.

13. (a)

(b)

(c)

14. (a)

(b)

(c)