Atoms, Ions, Isotopes, Oh My!

The mass number of an isotope is the sum of its ___ and ___.

• electrons, protons

• neutrons, electrons

• protons and neutrons

• atoms and molecules

What is the mass number of this atom?

• 7

• 14

• 21

• 28

Tags

NGSS.HS-PS1-8

Isotopes are atoms of the same element with ____.

• the same number of protons and neutrons

• different numbers of protons and electrons

• the same number of electrons and neutrons

• different numbers of protons and neutrons

How many neutrons does C-13 have?

• 6

• 7

• 12

• 13

The average atomic mass of potassium, K, is 39.098 amu. Potassium has three naturally occurring isotopes, K-39, K-40, and K-41. Which of these are in the most abundant in a 100 g sample of potassium?

• K-39

• K-40

• K-41

Answer explanation

The mass number on the periodic table is an average mass AND is the closest in mass to the mass of the isotope in a sample that has the largest mass.

How many valence electrons does this atom have?

• 16

• 8

• 32

• 6

Answer explanation

Valence electrons are the outermost electrons.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

How many valence electrons does this atom have?

• 19

• 20

• 39

• 8

• 1

Answer explanation

Valence electrons are the outermost electrons.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which electron(s) are involved in chemical reactions?

• green

• blue

• pink

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

In atoms, what is the maximum number of electrons that can occupy the first and second electron shells, respectively?

• 2,8

• 1,5

• 2,4

• 1,9

What would be the charge on this atom if it were to become an ion?

• 1-

• 2-

• 2+

• 2-

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2