Chemistry II. Matter

The definition of isotope is ..

• two or more atoms of the same element with same number of protons but different number of neutrons.

• two or more atoms of the same element with same number of protons but different number of electrons.

• two or more atoms of the same elements with same number of nucleon but different number of neutrons.

• two or more atoms of the same element with same number of electrons but different number of neutrons.

In a correctly written symbol what would be located in the "A" position?

• number of neutrons

• atomic number @ proton number

• number of electrons

• mass number @ nucleon number

An atom has 12 protons and 13 neutrons in its nucleus. Which is the correct symbol?

• 
• 
• 
• 

How many neutrons does the isotope of lithium have?

• 8
• 3
• 4
• 5

What does the mass number of an element represent?

• The number of protons in an atom

• the number of neutrons in an atom

• the number of electrons in an atom

• the number of protons and neutrons in an atom

What does it happen to this atom?

• It LOSES electrons

• It GAINS electrons

• It GAINS protons

• It LOSES protons

A formula with the lowest whole number ratio of elements in a compound is called

• Molecular Formula

• Chemical Formula

• Empirical Formula

• Distance Formula

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇
• C₂H₄O₂ and C₆H₁₂O₆
• C₃H₆O₃ and C₂H₆O₂
• CH₄ and C₂H₆

What is the empirical formula for hydrogen peroxide which has a molecular formula of H₂O₂?

• HO

• H₂O₂

• H₂O

The empirical formula for a compound is CH₂ and its relative atomic mass (A_r) is 70. What is its molecular formula? Use the periodic table to help you.

• CH₂

• C₅H₁₀

• C₇₀H₁₄₀