Atoms and Chemical Formulas

Formulas written on the left side of the arrow symbol and are the starting substances or ingredients in a chemical reaction.

• subscript

• coefficient

• reactant

• product

A number written in front of a chemical formula to show how many molecules of that substance are present.

• chemical formula

• coefficient

• reactant

• compound

Formulas written on the right side of the arrow symbol and are the new substances formed in a chemical reaction.

• subscript

• coefficient

• reactant

• product

The smallest unit of an element.

• atom

• element

• molecule

• compound

Tags

NGSS.MS-PS1-1

A substance composed of 2 or more elements chemically combined and in a set ratio.

• compound

• chemical equation

• formula

• product

A combination of symbols and chemical formulas used to describe what happens in a chemical reaction. It can include plus signs and an arrow.

• chemical formula

• chemical equation

• chemical reaction

• physical change

Matter is not created nor destroyed, only changed. The number of atoms in the reactants must equal the number of atoms in the product.

• chemical formula

• chemical equation

• law of conservation of mass

• precipitate

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A tall number in front of a chemical formula. It indicates the number of molecules present.

• Coefficient

• Subscript

• Exponent

• Coordinator

What does the subscript in a chemical formula tell you?

• How many molecules are present

• How many atoms are present

• How many elements are present

• How many neutrons are present

What is the correct chemical formula for the compound pictured?

• H₂

• H₂O

• O₂

• H₂O₂

Tags

NGSS.MS-PS1-1