Atoms, Elements and Mixtures

The chart below lists some substances and their symbols. How many of these substances are examples of elements?

• 1

• 2

• 3

• 4

Mixtures are different than pure substances because mixtures-

• have lower boiling points

• can be separated physically

• are less dense than pure substances

• contain only one type of atom

Beatriz wants to make a mixture out of her bowl of blueberries. Which of the following would turn her bowl of blueberries into a mixture?

• adding more blueberries to the bowl

• adding raspberries to the bowl

• cutting up the blueberries

• mashing the blueberries

These are mixtures that are the same throughout. 

• homogeneous mixtures 
• heterogeneous mixtures 
• mixed mixtures 

Concrete is a ______.

• mixture 
• compound 
• element 

How many protons in a neutral lithium atom?

• 3

• 7

• 4

• 1

How many protons in a neutral lithium ion (Li⁺¹)?

• 3

• 7

• 4

• 2

How many protons in a neutral oxygen atom?

• 8

• 7

• 10

• 16

What is a representation of an ion?

• Li

• Na-22

• O^-2

What charge does an atom have when it GAINS electrons?

• Positive

• Negative

• Neutral