Counting Atoms and Elements

Front

What is an element in chemistry?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means and is made up of atoms that all have the same number of protons.

Front

How many elements are represented in the formula HNO₃?

Back

3

Tags

NGSS.MS-PS1-1

Front

What is the total number of atoms in the chemical formula C₈H₃NaBr₁₂?

Back

24

Tags

NGSS.MS-PS1-1

Front

How many atoms of Hydrogen are in the compound H₂O?

Back

2

Tags

NGSS.MS-PS1-1

Front

What are element symbols?

Back

Element symbols are one or two-letter notations used to represent elements, consisting of a single uppercase letter or an uppercase letter followed by a lowercase letter.

Front

How many Nitrogen atoms are in the compound (NH₄)₂CrO₄?

Back

2

Tags

NGSS.MS-PS1-1

Front

What is the significance of subscripts in a chemical formula?

Back

Subscripts indicate the number of atoms of each element in a molecule; for example, in H₂O, the '2' indicates there are two hydrogen atoms.

Tags

NGSS.MS-PS1-1

Front

What is the difference between a molecule and a compound?

Back

A molecule is a group of two or more atoms bonded together, while a compound is a type of molecule that contains at least two different elements.

Tags

NGSS.MS-PS1-1

Front

How do you determine the number of atoms in a chemical formula?

Back

To determine the number of atoms, add the subscripts of each element in the formula; if no subscript is present, it is assumed to be 1.

Tags

NGSS.MS-PS1-1

Front

What does the formula (NH₄)₂CrO₄ represent?

Back

It represents ammonium chromate, which contains ammonium ions and chromate ions.

Tags

NGSS.MS-PS1-1