1 Chemistry Review

Convert 0.0025 kg into grams.

• 0.25 grams
• 25 grams
• 0.0025 grams
• 2.5 grams

Express 2300 metres in scientific notation.

• 2.3 x 10^2
• 2.3 x 10^4
• 2.3 x 10^-3

• 2.3 x 10^3

Express 0.0045 in scientific notation.

• 4.5 x 10^3

• 4.5 x 10^-2
• 4.5 x 10^-3
• 4.5 x 10^-4

How many significant figures are in 0.0320?

• 3
• 4
• 2
• 1

How many protons does magnesium have?

• 12

• 24

• 2+

• 2

How many electrons does a potassium atom have?

• 39

• 19

• 1+

• 20

How many electrons does chlorine ion have?

• 17

• 35

• 18

• 1-

What is the ionic charge of group 15 elements?

• 5+

• 3-

• 3+

• 5-