Question

True or False.

(a) Effective nuclear charge (Zeff) is the positive charge experienced by the electron from the nucleus and it increases from left to right across the period. Answer: __________

(b) Effective nuclear charge slightly decreases going down a group. Answer: __________

(c) Zeff for calcium is smaller than that of chlorine. Answer: __________

(d) Atomic radius tends to decrease from top to bottom of a group because of the increase in the principle quantum number. Answer: __________

(e) Anions are larger than their parent atoms because electrons are added to the valence shell reducing the electron-electron repulsions. Answer: __________

(f) Al3+ is larger than Na+ because Na+ has two extra electrons. Answer: __________

(g) The ionization energy of Na2+ is significantly higher than Na+ because it takes more energy to remove the inner-shell electron. Answer: __________

(h) Bromine, calcium and sodium are metallic elements because they are on the left side of the periodic table. Answer: __________

(i) Calcium, antimony, and silicon are metalloids that their properties fall between those of metals and those of nonmetals. Answer: __________

(j) Lattice energy is the energy required to completely separate one mole of solid ionic compound into its gaseous ions and it is always a negative number. Answer: __________

Answer 1

a). True

b).True

c).True

d).False ( atomic radious increases in a group from top to bottom because the principle quantam number increases)

e).True

f).false ( Al+3 ion is smaller than Na+ because the +ve charge increases on the metal atom , attractive power of Nuclous increases over the remaining electrons. so the size of the ion decreases.)

g).True.

h).False. ( Bromine is a nonmetal,and which is present at the right side of the periodic table)

i).False ( Calcium is a metal)

j).True.