Atoms, elements,

and the periodic

tableMR. BANKS

7TH GRADE SCIENCE

Matter

Matter is anything that

has mass and takes up

space.

Atoms

All matter is made out

of atoms.

Atoms are the smallest

particles of matter that

can be called an

element.

Atoms are the building

blocks of all matter.

Atoms

Atoms are VERY tiny.

About a million atoms

stacked on top of each other

= the thickness of a sheet of

paper.

About 5 million atoms make

up a period at the end of a

sentence.

Elements

There are many different

types of atoms, those

different types are called

elements.

We now know of 118

different elements.

The first 92 elements can be

found in nature.

The rest we have created in

a laboratory.

Elements

Think of atoms like

Legos, different

elements are like

different shapes/colors

of Lego.

These Legos can be

combined with

different Legos or

others of the same type

to create things.

Periodic table

The periodic table is an

organized list of all the

known elements.

Each square represents

an element.

Information about each

element is written on the

squares.

Each element is

represented by an

atomic symbol

consisting of one or two

letters.

The symbol is used as a

code for doing

chemistry.

Periodic table entry

Atomic Symbol

Element Name

Each element has an

atomic number,

elements are arranged

in order of increasing

atomic number.

Periodic table entry

Atomic Symbol

Element Name

Atomic number

Non-metals

Metals

What the periodic table would

look like if the lanthanides and

actinides were in the right place.

Dimitri Mendeleev

1834 – 1907

Russian chemist

Organized the periodic

table by atomic weight

using the 65 known

elements.

Left gaps in places where

he predicted new elements

would be discovered later

(and was correct).

He noticed patterns and

similarities in the elements.

Dimitri Mendeleev

Mendeleev’s periodic table.