8th Chemistry

Periodic Table

1

What are the 3 main sections of the Periodic Table?

metals, nonmetals, and metalliods

2

What are the columns called on the Periodic Table?

group or family

3

What are the rows called on the Periodic Table?

periods

4

What is special about electrons of atoms in the same group/family?

same number of valence electrons

5

What information is on one tile of the Periodic Table?

element name, element symbol, atomic number, and atomic mass

Chemical Bonds

1

What are the electrons on the outer level of an atom called?

valence electrons

2

What kind of bond is between positively and negatively charged atoms?

ionic bond

3

What has a slightly positive end and a slightly negative end because of unequal sharing of electrons?

polar molecule

4

What kind of bond is formed when positively charged atoms share their electrons.

metallic bond

5

What type of bond is formed when two atoms share one or more pairs of valence electrons?

covalent bond

Chemical Reactions

1

What kind of reaction has two reactants and two products?

single-replacement reaction

2

Distinguish between endothermic and exothermic reactions.

endothermic = absorbs energy/heat

exothermic = releases energy/heat

3

What kind of reaction occurs when a substance combines with oxygen and releases energy?

combustion

4

What lowers the activation energy of a reaction or chemical formula in an equation?

catalyst

5

What is the name of the starting substance and produced substance of a chemical reaction?

reactant and product

Acids & Bases

1

What does pH stand for?

potential for Hydrogen

2

Temperature and pressure can change what component of a solute?

solubility

3

What kind of mixture has individual components that you can see?

heterogeneous

4

What kind of mixture has individual parts that you cannot see?

homogeneous

5

What do bases and what do acids release in a solution?

base: hydroxide ions

acid: hydrogen ions

Chemical Equations

1

What is the number placed in front of an element symbol or chemical formula in an equation called?

coefficient

2

What is the small number placed after an element in a chemical equation called?

subscript

3

What does the arrow mean in a chemical equation?

a reaction has happened

4

O₂ + 4H₃

_{How many hydrogen atoms are in the formula?}

12

5

Balance the chemical equation. 

___ Li + ___ F₂ --> ___ LiF

_2_ Li + ___ F₂ --> _2_ LiF