Chemistry Unit 2 Review

24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu.
What is the average mass of this element?

• 74.92 amu
• 24.97 amu
• 75.01 amu
• 74.51 amu

An element with 4.35% have a mass of 49.9461 amu, 83.79% have amass of 51.9405 amu, 9.50% have a mass of 52.9407 amu, and 2.36% have a mass of 53.9389amu.

• 51.99 amu
• 52.19 amu
• 53.45 amu
• 17.33 amu

The horizontal row on the periodic table is called a

• group
• family
• period
• atomic number

A vertical column is called...

• group
• tower
• period
• crew

Most of the elements on the periodic table are classified as _____.

• Metals
• Nonmetals
• Metalloids
• Periods

Which group of the periodic table are the noble gases?

• 1A

• 2A

• 3A

• 4A

The atoms along the staircase are called 

• metals
• nonmetals
• metalloids
• noble gases

How many valence electrons does Chlorine have?

• 5
• 2
• 7
• 5

How many total electrons would P^-3

• 5

• 8

• 15

• 18

How many neutrons does uranium-235 have?

• 238
• 92
• 146
• 143