Question 14 1 pts
Reactivity is defined as the capacity of a unit of matter, such as an atom, to undergo a
chemical reaction with another unit of matter. An atom's reactivity is determined by the
number of
-electrons in its outer shell
-protons in its outer shell.
-protons and neutrons in its nucleus
-electrons and protons in its nucleus.

Question 15
1 pts
A certain element exists at room temperature as a brittle solid. When tested, it is a poor
conductor of electricity. This element is most likely classified as
-a noble gas
-a metalloid.
-a nonmetal.
- a halogen

Compared to other metals, the alkali metals have relatively low melting points. Which of
the following best explains this property of alkali metals?
-Alkali metals react readily with water vapor in warm air.
-Alkali metals form diatomic molecules that have little attraction to each other.
-Ionic bonds break more easily than covalent bonds.
-Metallic bonds are weakest for metals with few electrons.

1
Question 17
The elements copper and iron are found in the section of the periodic table for
-alkali earth metals.
-transition metals.
-alkali metals.
-metalloids.

Paul made a list about alkaline earth metals.
Alkaline Earth Metals
.

gain two electrons
• are found in group two
ions will be negative two
• include elements Be, Mg, Ca

Paul made a mistake on his list. Which best describes the mistake Paul made?

-Alkaline earth metals do not gain two electrons; they lose two electrons.
-Alkaline earth metals are not found in group two; they are found in group one.
-Alkaline earth metal ions will not be negative two: the ions will be positive two.
-Alkaline earth metals do not include elements Be Mg and Car they include Co, Ni, and Cu.

On the periodic table, the elements in the columns have the same
-density
-atomic mass.
-physical properties.
-number of valence electrons.

The list in the box below shows three different substances.
1. Lithium
11. Sodium
M. Potassium
Which of the following statements is correct about all of these substances?
-They have the same atomic number because they are in the same class.
-They have the same atomic mass because they are in the same series.
-They share chemical properties because they are in the same group.
-They share physical properties because they are in the same period.

A sample of an unknown element, Xx, exhibits the following properties.
• Reacts with oxygen to form Xxo
• Has a silver metallic luster
• Has a low melting point
To which chemical family does element Xx most likely belong?
-metalloids
-transition metals
-alkaline earth metals
-alkali metals