Difference Between Elements and Compounds

How do elements and

compounds compare and

how do they differ?

What are
elements ?
● They are the

simplest pure
substance that
cannot be
broken into
simpler
substances

● Consist of only

one type of atom

● Found on the

periodic table

● Can be a single capital letter OR a capital letter followed by a lowercase

letter which is called a chemical symbol

What are compounds ?

● They are a pure substance

that have been chemically
combined

● Formed from 2 or more

elements

● Written as a ratio of

elements called a chemical
formula

● Will always have 2 or more

capital letters !

H2O

hydrogen

oxygen

CaCO 3

calcium

carbon

oxygen

What are atoms ?

● Atoms are the smallest unit

of an element

● Each element has a unique

type of atom

● Think of atoms as individual

Lego pieces

● Can you name the atoms of

elements on this slide?

He

P

C

P

C

He

B

B

Na

Na

Na

K

K

K

What are molecules ?

● They are 2 or more atoms

● Can be 2 atoms of the

same element

● Can be 2 or more atoms of

different elements

● Think of it as structures

built from your Lego pieces

Recap!

Elements

Compounds

pure substance

chemical symbol

atom

Na

O2

molecule

B

pure substance

chemical formula

CO2
CaCO

3

molecule

practice!

Can you identify whether each one of the following is an
element or a compound? Which ones are molecules?

I2
H2O

Ca

Fe

CH3COOH

H

NaCl

O2
CH4