Matter Unit Review

A quick way to determine how many valence electrons an atom has is to

• look at the period it is in

• look at the group it is in

• look at the atomic number

• draw a model and count them

What period is this element in?

• 17

• 7

• 3

• 5

What two things does the atomic number tell you?

• The number of protons and electrons in an atom

• The number of protons and neutrons in an atom

• The number of electrons and neutrons

• The mass of the atom

What are valence electrons?

• Any electron in an atom

• The electrons closest to the nucleus

• The electrons on the outer energy shell

• The total number of electrons

What element is represented by the atom model above?

• Magnesium

• Calcium

• Neon

• Chromium

Tags

NGSS.MS-PS1-1

How do you find the number of neutrons an atom has?

• Protons + electrons = neutrons

• Atomic number + atomic mass = neutrons

• atomic number - Protons = neutrons

• Atomic mass - atomic number = neutrons

An atom is stable if...

• It has 10 or more electrons

• It is on the left side of the periodic table and as only 1 electron on the outer shell

• It is on the right side of the periodic table and It has an almost full outer shell

• It is on the right side of the periodic table, and it has 8 electrons in the outer shell

The most basic unit of matter is

• a molecule

• an atom

• a symbol

• an element

A pure substance that cannot be broken down into any other substance

• atom

• element

• molecule

• compound

Tags

NGSS.MS-PS1-4

Two or more different elements that are combined chemically

• atom

• element

• compound

• molecule