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