2223 CS Unit 2-4 Review

Which of the following elements forms a 1+ ion?

• fluorine (#9)

• radon (#86)

• francium (#87)

• helium (#2)

Answer explanation

Remember, to form a 1+ ion an atom needs to lose an electron. Group 1 metals lose 1 electron to be like the Noble Gas in the period above.

An atom with 17 protons, 18 neutrons, and 17 electrons could be:

• Argon - 35

• Chlorine - 35

• Argon - 18

• Chlorine - 34

Answer explanation

Remember, the number of protons determines the atomic number (and which element). The mass number comes from the number of protons and neutrons. This type of notation uses the name of the element and the mass number.

Which of the following could have 15 protons, 16 neutrons, and 18 electrons.

• P^3-

• P³⁺

• Ar^3-

• Ar³⁺

Answer explanation

The number of protons determines the atomic number and the element. The protons minus the electrons will get you the charge.

the name for IF₃ is ​ (a)  

• iodine trifluoride
• monoiodine trifluoride
• iodine fluoride

Match the following

• CO

• carbon dioxide

• C₂H₆

• tetracarbon hexahydride

• C₄H₆

• dicarbon tetrahydride

• CO₂

• dicarbon hexahydride

• C₂H₄

• carbon monoxide

According to the Law of Conservation of Matter, the mass of the reactants must be _____ the mass of the products.

• greater than

• less than

• equal to

In order to balance a chemical equation, you can change the

• coefficients

• subscripts

• formulas

• elements

What type of reaction is 2 NaOH + Li₂SO₄ --> Na₂SO₄ + 2 LiOH

• single replacement

• double replacement

• combination

• decomposition

The products of a combustion reaction are always

• a hydrocarbon and oxygen

• oxygen and carbon dioxide

• carbon dioxide and water

• water and a hydrocarbon

The coefficients that balance the following equation are:

__ Al + __ O₂ --> __ Al₂O₃

• 1,1,1

• 4,3,2

• 2,3,4

• 2,3,1