8th Grade 6.6C,8.12B,7.6C,7.11AB Review

The periodic chart is organized into 3 main categories. Choose all of them.

• Metals

• Solids

• Nonmetals

• Metalloids

What does the subscript "3" in the chemical formula Al₂O₃ indicate?

• 3 Aluminum atoms in the molecule

• 3 Oxygen atoms in the molecule.

• There are 3 molecules in Aluminum Oxide.

• There are 3 atoms of both Aluminum and Oxygen in the molecule.

Which of the following formulas represents a compound with 1 Calcium atom and 2 Chlorine atoms?

• CaCl

• Ca₂Cl

• CaCl₂

• Ca₂Cl₂

Which of the following best describes the formula CaCO₃?

• 1 Calcium, 1 Carbon, and 3 Oxygen

• 1 Calcium, 3 Carbon, and 3 Oxygen

• 3 Calcium, 1 Carbon, and 1 Oxygen

• 3 Calcium, 3 Carbon, and 1 Oxygen

In the chemical equation 2 H₂ + O₂ --> 2 H₂O, what does the coefficient "2" in the front of H₂O indicate?

• There are 2 Hydrogen atoms in each molecule of water.

• There are 2 Oxygen atoms in each molecule of water.

• There are 2 molecules of water produced in the reaction.

• There are 2 molecules of Hydrogen used in the reaction.

In the chemical formula for Magnesium Hydroxide, Mg (OH) ₂ what does the subscript "2" outside the parenthesis indicate?

• There are 2 Magnesium atoms in the molecule.

• There are 2 Oxygen atoms and 2 Hydrogen atoms in the molecule.

• There are 2 molecules of Magnesium Hydroxide.

• There are 2 Hydroxide (OH) ions in the molecule.

Metals have a tendency to bond with nonmetals to make compounds. Which element is most likely to bond with Mg to form a compound?

• K

• Al

• Si

• Cl

Metals are located on the ________ of the periodic chart.

Which of the following statements correctly describes how to identify the number of atoms in a chemical formula? Select all that apply.

• The subscript number following an element symbol indicates the number of atoms of that element in the molecule.

• A coefficient before a chemical formula multiplies the number of each type of atoms in the formula by that coefficient.

• The element with the lowest subscript number is the most abundant in the compound.

• If there is no subscript number after an element symbol, it means there is only one atom of that element.

Ammonium Nitrate (NH₄NO₃) is commonly used in fertilizers. How many atoms of N are represented in the formula?

• 5

• 2

• 3

• 1