Section 8.3- Periodicity of Chemical Properties

Question 1

the first three alkali metals- LI, Na, and K- all have lower densities that __________________, are soft enough to be cut with a _______________, and melt at relatively __________ temperatures for metals

Answer 1

less dense than water (will float)
cut by knife
melt at low temps

Question 2

chemical reactivity ___________________ as you go further down the periodic table groups

Answer 2

increases

Question 3

the alkali metals are also active enough to react with hydrogen at elevated temperatures to form

Answer 3

hydrides

Question 4

hydrides react with water to produce

Answer 4

hydrogen gas and metal hydroxide
(K + H2O = H2 + KOH)

Question 5

the group 2 elements- alkaline earth metals- have reactions similar to those of group 1 metals, but the reactions are _______________ vigorous

Answer 5

less

Question 6

included in group 2 elements

are silvery-white, malleable, and ductile

are less soft and have higher densities and melting points than the alkali metals

are less reactive, but still too reactive to be found in nature as the free metals

exist as 2+ ions

Answer 6

alkaline earth metals (Mg, Ca, Sr, and Ba)

Question 7

alkaline earth metals react with _______________ to form the metal chlorides

Answer 7

halogens

Question 8

as we proceed across a period, there is a repeated pattern to certain properties; one of these properties is the

the number of atoms with which an element may combine

Answer 8

combining capacity of the elements

Question 9

the ________________ of elements within the same group and the _____________ of the resulting compounds are similar

Answer 9

reactions
formulas