8th Science RE-TEST Valence, Isotopes, ions, matter

Where are valence electrons located?

• They are in the nucleus of the atom

• They are in the outermost energy level of the atom

• They are in the first energy level of the atom

• They are not in an atom

Why are valence electrons important?

• They help in bonding between atoms

• They contribute to the mass of the atom

• They determine how the atom looks

• They create the atom's atmosphere

Chlorine has atomic number 17. How many valence electrons does chlorine have?

• 2

• 8

• 7

• 17

Beryllium (Be) is in group 2A. How many valence electrons does it have?

• 1

• 2

• 4

• A

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Krypton (Kr) is in group 8A. How many valence electrons does it have?

• 2

• 8

• 36

• 18

Nitrogen is in group 5A and thus has 5 valence electrons. How many dots would you need to draw for the Lewis Dot Structure of Nitrogen.

(a)  

Sulfur is in group 6A. Which is the correct Lewis Dot Structure?

• 
• 
• 
• 

Tags

NGSS.HS-PS1-1

A water molecule is a neutral particle because it has equal numbers of ___ and ___.

• electrons, protons, and neutrons

• electrons and neutrons

• protons and neutrons

• protons and electrons

Tags

NGSS.MS-PS1-1

Two atoms of different elements will definitely find different numbers of _____ in each atom.

• Nuclei

• Protons

• Neutrons

• Electrons

What is the mass number of this Neon atom?

(a)  

Tags

NGSS.MS-PS1-1