Which of the following is a nonmetal?

• Arsenic

• Oxygen

• Magnesium

• Iron

Answer explanation

Oxygen is a nonmetal, making it the correct choice among the options provided.

Which of the following elements is an alkali metal?

• helium (He)

• iron (Fe)

• barium (Ba)

• potassium (K)

Answer explanation

The alkali metal in the list is potassium (K). Alkali metals are found in Group 1 of the periodic table, and potassium is one of them.

What group on the periodic table are halogens in?

• Alkali metals

• Group 17

• Period 5

• Group 12

Answer explanation

Halogens are in Group 17 on the periodic table, making Group 17 the correct choice.

Elements in the same _______ have the same number of valence electrons

Answer explanation

Do elements in the same group have the same number of valence electrons

What group on the periodic table are noble gases in?

• 15

• 18

• 10

• 20

Answer explanation

Noble Gases are in the 18th period of the Periodic Table.

Which element has an atomic number that is four more than the noble gas in period 2?

• Oxygen (O)

• Nitrogen (N)

• Silicon (Si)

• Boron (B)

Answer explanation

The element with an atomic number four more than the noble gas in period 2 is Silicon (Si).

What does an element's atomic number represent?

• Number of protons in the nucleus of an atom

• Number of neutrons in the nucleus

• Number of electrons in the outer shell

• Number of isotopes in the element

Answer explanation

Number of protons in the nucleus of an atom

What does an element's atomic mass represent?

• The atomic mass of an element represents the density of the element.

• The atomic mass of an element represents the average mass of an atom of that element.

• The atomic mass of an element represents the number of electrons in its outer shell.

• The atomic mass of an element represents the number of protons in its nucleus.

Answer explanation

The atomic mass of an element represents the average mass of an atom of that element.

How many valence electrons does an element in group 1 have?

• 2

• 7

• 10

• 1

Answer explanation

An element in group 1 has 1 valence electron, making the correct answer 1.

A __________ is a positively charged ion.

Answer explanation

A cation is a positively charged ion.