Chapter 5

Question 1

An element that is a very reactive gas is most likely a member of the

Answer 1

halogens

Question 2

Alkaline-earth metals ____ than alkali metals.

Answer 2

have greater density

Question 3

The element ____ is a metalloid.

Answer 3

Silicon SI

Question 4

The elements in Groups 3–12

Answer 4

are solids at room temperature, except for mercury.

Question 5

is a gas at room temperature, and its atoms have six electrons in their outer level.

Answer 5

Oxegyn

Question 6

the atomic mass of mercury

Answer 6

80

Question 7

Which of the following statements is NOT true of elements on the periodic table?

Answer 7

Elements to the left of the zigzag line are metalloids.

Question 8

Which of the following metals is most reactive?

Answer 8

lithium (Li)

Question 9

Atoms of most nonmetals have ____ electrons in their outer energy level.

Answer 9

an almost complete set of

Question 10

Which class of elements are also called semiconductors?

Answer 10

metalloids

Question 11

The group of metals that are soft enough to be cut with a knife are

Answer 11

alkali metals.

Question 12

Alkali metals are the most reactive of all the metals because they have ____ electron(s) in their outer energy level.

Answer 12

1

Question 13

Why would you NOT want to handle alkali metals with your bare hands?

Answer 13

Alkali metals can react with the moisture on your hands and burn your skin.

Question 14

Why are alkaline-earth metals less reactive than alkali metals?

Answer 14

It is more difficult for atoms to give away two electrons than to give away one electron

Question 15

Why are halogens considered to be the most reactive group of nonmetals?

Answer 15

Their atoms gain only one electron to have a complete outer level.

Question 16

Which of the following is a property of nonmetals?

Answer 16

poor conductors of electric current

Question 17

Hydrogen’s physical properties are more like the properties of

Answer 17

nonmetals than of metals.

Question 18

Which of the following elements are used to make computer chips?

Answer 18

silicon and germanium

Question 19

An element found in the ____ makes up about 80 percent of the air you breathe.

Answer 19

nitrogen group.

Question 20

Groups 3–12 are commonly referred to as

Answer 20

transition metals.

Question 21

Lanthanides and actinides are placed at the bottom of the periodic table

Answer 21

to keep the periodic table from being too wide.

Question 22

All atoms of actinides

Answer 22

are radioactive.

Question 23

Rust is an example of how some transition metals

Answer 23

are very reactive

Question 24

Which element would be the most reactive with potassium?

Answer 24

bromine (Br)

Question 25

Which element is in the same period as sodium (Na) and in the same group as iodine (I)?

Answer 25

chlorine (Cl)

Question 26

Atoms of elements in the same group as oxygen have ____ electrons in their outer level.

Answer 26

6

Question 27

The atomic number of the atom represented by the model is

Answer 27

2

Question 28

The atom represented by the model makes up an element that belongs to which group on the periodic table?

Answer 28

Group 18—noble gases

Question 29

The element made up of atoms like the one in the model should be

Answer 29

unreactive.

Question 30

The element composed of atoms like the one in the model is found in which period on the periodic table?

Answer 30

Period 1

Question 31

What causes the properties of elements in a group to be similar?

Answer 31

Having the same number of electrons in the outer level of their atoms causes the properties of elements in a group to be similar.

Question 32

Why are neither the alkali metals nor the alkaline-earth metals found uncombined in nature?

Answer 32

They are so reactive that they react with water or oxygen in the air.

Question 33

Using the periodic table, determine which two groups have highly reactive metals.

Answer 33

Groups 1 and 2 (on the left) have highly reactive metals.

Question 34

Describe the location of metals, metalloids, and nonmetals on the periodic table

Answer 34

Metals are located to the left of the zigzag on the periodic table. Metalloids border the zigzag. Nonmetals are to the right of the zigzag.

Question 35

This metal is very reactive, has properties similar to magnesium, and is in the same period as bromine.

b. This nonmetal is in the same group as lead.
c. This metal is the most reactive metal in its period and cannot be found uncombined in nature. Each atom of the element contains 19 protons.

Answer 35

. calcium

b. carbon
c. potassium