Question

1.

Which of the following describes the element Cs.
Choose all that apply.

a.consists of diatomic molecules in elemental form

b.is found in nature only combined with other elements

c.reacts vigorously with alkali metals to form salts

d. is very reactive as a metal

e.forms a basic solution in water

f. is one of the group of the least reactive elements

2. Using only the periodic table arrange the following elements in order of increasing atomic radius:

boron, fluorine, oxygen, lithium

Smallest____
______
______
Largest_____

3. Using only the periodic table arrange the following elements in order of increasing atomic radius:

nitrogen, antimony, arsenic, bismuth

Smallest_____
________
________
Largest_____

Please answer this question according to the general rules you have learned regarding periodic trends. DO NOT base your answer on tabulated values since exceptions may occur.

Please answer this question according to the general rules you have learned regarding periodic trends. DO NOT base your answer on tabulated values since exceptions may occur.

Answer 1

Question 1.

Which of the following describes the element Cs.
Choose all that apply.

a.consists of diatomic molecules in elemental form FALSE, it is a metal, so it is a metallic netweork of Cs atoms

b.is found in nature only combined with other elements. TRUE, since Cs is very reactive, will not be present as Cs(s)

c.reacts vigorously with alkali metals to form salts. FALSE, reacts with nonmetals to form salts

d. is very reactive as a metal. TRUE, this is very reactive due to its lone electron in its valence shell

e.forms a basic solution in water. TRUE, since Cs + H2O = Cs(OH) + H2(g), OH- is basic

f. is one of the group of the least reactive elements. FALSE, it is pretty reactive

2. Using only the periodic table arrange the following elements in order of increasing atomic radius:

boron, fluorine, oxygen, lithium

Recall that from the preiodic table we get:

Li, B, O, F

note that as we go from lef tto right, the number of electrons increases, therefore the proton/electron interaction increases as well, this decreases the distanc ebetween the species, therefore, the apparent radius of the atom decreases

so

Li > B > O > F

Question 3. Using only the periodic table arrange the following elements in order of increasing atomic radius:

nitrogen, antimony, arsenic, bismuth

N, Sb, As, Bi

Note that they appear to be in the SAME family, i.e. column in the preiodic table

then

actual numerical order is N < As < Sb < Bi

Clearly, they have the SAME amount of electrons in its valence shell, so the onlyh effect increasing the size is total number of protons in the nucleus

therefore:

N < As < Sb < Bi