ISBS #19-24, p. 51

19) For each of the following elements, identify the number of protons or electrons needed for an electrically neutral atom.

a. carbon: 6 protons, 6 electrons.
b. aluminum: 13 protons, 13 electrons.
c. lead: 82 protons, 82 electrons.
d. chlorine: 17 protons, 17 electrons.

20) Decide whether each of the following atoms is electrically neutral.

a. sulfur: 16 protons, 18 electrons. No.
b. iron: 26 protons, 24 electrons. No.
c. silver: 47 protons, 47 electrons. Yes.
d. iodine: 53 protons, 54 electrons. No.

21) Classify each of the following as an electrically neutral atom, an anion, or a cation.

a. O^2-: anion
b. Li: electrically neutral atom.
c. Cl: electrically neutral atom.
d. Ag+: cation.
e. Hg^2+: cation

22) For each particle in Question 32, indicate whether the electrical charge or lack of electrical charge was from a neutral atom gaining electrons, losing electrons, or neither.

a. O^2-: gaining electrons.
b. Li: neither.
c. Cl: neither.
d. Ag+: losing an electron.
e. Hg^2+: losing electrons.

23) Write the symbol and show the electrical charge (if any) on the following atoms or ions:

a. hydrogen with 1 proton and 1 electron: H
b. sodium with 11 protons and 10 electrons: Na+
c. chlorine with 17 protons and 18 electrons: Cl-
d. aluminum with 13 protons and 10 electrons: Al^3+

24) Write the name and formula for the ionic compound that can be formed from these cations and anions:

a. Potassium iodine: KI
b. Calcium sulfide: CaS
c. Iron(iii) bromide: Fe^3+(Br-)3: (Fe)(Br)3
d. Barium hydroxide: Ba^2+ + (OH-)2: (Ba)(OH)2
e. Ammonium phosphate: (NH4+)3 + PO4^3-: (NH4)3(PO4)
f. Aluminum oxide: (Al^3+)2 + (O^2-)3: (Al)2(O)3