Atoms
Structure of Atoms

Atoms are made up of subatomic particles:
Structure of Atoms

Atoms are made up of subatomic particles:
- Protons; positively charged, and this number is the
atomic number.
Structure of Atoms

Atoms are made up of subatomic particles:
-
Protons; positively charged, and this number is the
atomic number.
-
Neutrons; no charge and described as being
neutral.
Structure of Atoms

Atoms are made up of subatomic particles:
-
Protons; positively charged, and this number is the
atomic number.
-
Neutrons; not charge and described as being
neutral.
-
Electrons; negatively charged.
Structure of Atoms

Atoms are made up of subatomic particles:
-
Protons; positively charged, and this number is the
atomic number.
-
Neutrons; not charge and described as being
neutral.
-
Electrons; negatively charged.
-
Protons and neutrons form the nucleus of the atom,
with the electrons moving in the space around the
nucleus
Structure of Atoms

Atoms are made up of subatomic particles:
-
Protons; positively charged, and this number is the
atomic number.
-
Neutrons; not charge and described as being
neutral.
-
Electrons; negatively charged.
-
Protons and neutrons form the nucleus of the atom,
with the electrons moving in the space around the
nucleus
-
https://www.youtube.com/watch?v=lP57gEWcisY
Mass & Atomic numbers

Mass number is the number of protons plus the
neutrons in the nucleus.
Mass & Atomic numbers

Mass number is the number of protons plus the
neutrons in the nucleus.

Atomic number is the number of protons (and the
number of electrons as they are equal) .
EG.

Sodium – 11 protons and 12 neutrons.

What’s its atomic and mass number?
Isotopes

Are two or more atoms which have the same
number of protons but a different number of
neutrons.
Isotopes

Are two or more atoms which have the same
number of protons but a different number of
neutrons.

The chemical properties of isotopes are the same
(however they have a different mass) so it’s
impossible to tell the difference in a chemical
reaction.
Isotopes

Common isotopes are:
-
carbon-12 and carbon-14
-
Oxygen-16 and oxygen-18

http://www.youtube.com/watch?v=zEX2aGpIDBY
Electron arrangement on the
periodic table
Electron arrangement on the
periodic table

Moving across a row of the periodic table, the outer
shell increases by one electron, but each element
has the same outer electron shell.
Electron arrangement on the
periodic table

Moving across a row of the periodic table, the outer
shell increases by one electron, but each element
has the same outer electron shell.

The last element in each row has a full outer shell
Electron arrangement on the
periodic table

Moving across a row of the periodic table, the outer
shell increases by one electron, but each element
has the same outer electron shell.

The last element in each row has a full outer shell

Elements are stable, or unreactive when their
outermost shell is full.
Electron arrangement on the
periodic table

Moving across a row of the periodic table, the outer
shell increases by one electron, but each element
has the same outer electron shell.

The last element in each row has a full outer shell

Elements are stable, or unreactive when their
outermost shell is full.
EG – Ne: 2,8 and Ar: 2,8,8 are both unreactive because
they have full outer shell.
Answer these
1.
A carbon atom has 6 protons and 8 neutrons.
a)
What is the number of electrons in an atom of
carbon?
b)
Write down the atomic number of carbon
c)
Describe how you know this atom is neutral
d)
Write the electron arrangement of carbon
Answer these
2. A Mg atom has 12 protons and 12 neutrons.
a)
What is the number of electrons in Mg?
b)
Draw a diagram of an Mg atom
c)
What is the mass number of Mg?
Answer these
3. An atom has atomic number 20 and mass number
42
a)
What is the number of protons in the atom?
b)
What is the number of neutrons in the atom?
c)
What is the element?