Write concise definitions for these

words

protonelectron

neutronshells

Atomic Structure – Inside the Atom

Dalton described the atoms as particles that cannot be split. However the atom is made of smaller sub-atomic particles

e.g.An atom of lithium

Atomic Structure – Inside the Atom

There are three types of particle inside the atom – protons, neutrons and electrons

Protons

Neutrons

Electrons

An atom of lithium

Atomic Structure – Inside the Atom

The sub-atomic particles have different charges and masses

Particle Charge Mass(in atomic

units)

Proton 1+ 1

Neutron 0 1

Electron 1- 0

Atomic Structure – Inside the Atom

Each element has its own atomic number, it tells us how many protons there are in one atom of that element.

Atomic number = number of protons

Atoms are neutral (they have no charge). So the number of electrons equals the number of protons.

Atomic Structure – Inside the Atom

Mass number tells us how many protons and neutrons there are in an atom..remember electrons are so small we approximate their mass to zero

Mass number = number of protons + number of neutrons

Isotopes

Atoms of the same element always have the same number of protons. However they may have different numbers of neutrons. There are known as isotopes. Carbon has two isotopes:

C C6

14

6

12

Write down the number of protons, neutrons and electrons in the two isotopes of carbon

Carbon-12 Carbon-14

Different isotopes of the same element may have different physical properties e.g. melting point or density. Some isotopes are radioactive

However they always have the same chemical properties.

A good example is hydrogen…

Hydrogen exists as 3 isotopes… although Hydrogen-1 makes up the vastmajority of the naturally occurring element.

H1

1 H2

1 H31

ProtonsElectronsNeutrons

Hydrogen

ProtonsElectronsNeutrons

(Deuterium)

ProtonsElectronsNeutrons

(Tritium)

All have a different mass, tritium is radioactive but all react with oxygen to form water

1. Which of the following is not a sub-atomic particle?

A. Proton.

B. Isotope.

C. Neutron.

D. Electron.

2. The element Cobalt has a relative atomic mass of 59 and an atomic number of 27. Which of these is a true statement about each neutral cobalt atom?

A. It contains 59 neutrons.

B. It contains 27 electrons.

C. It contains 32 protons.

D. It contains equal numbers of neutrons and electrons.

3. The Periodic Table displays iron as shown below. This indicates that Fe atoms:

A. contain 56 neutrons.

B. contain 30 electrons.

C. contain 26 protons.

D. contains more protons than neutrons.

56

Fe26

4. Bromine consists of a mixture of two isotopes: Bromine-79 and Bromine-81

• Which of the following is true:

A. Both isotopes contain 35 protons.

B. Bromine 79 contains 46 neutrons.

C. Bromine 81 contains 44 neutrons.

D. Bromine-81 is more reactive than bromine-79.

80Br35

5. Natural boron consists of approx. 20% boron-10 and 80% boron-11.

• What will the relative atomic mass of natural boron will be?

A. 10.0

B. 11.0

C. 10.5

D. 10.8

?B5

6. Which answer best describes the shell arrangement of the electrons in a sodium atom?

A. 2,8,1.

B. 2,2,7.

C. 2,8,8,3.

D. 2,8,8,1.

23Na11

7. Which answer best describes the shell arrangement of the electrons in an oxygen atom?

A. 2,8,6.

B. 2,8,8.

C. 2,8.

D. 2,6.

16O8

8. Which of these elements will have electron shells that are either full or empty (i.e. not partially full)?

14N7

A 40Ar18

B

40Ca20

C 27Al13

D

9. Which answer best describes the shell arrangement of the electrons in an oxide ion O2-?

A. 2,8,6.

B. 2,8.

C. 2,8,8.

D. 2,6.

16O8