1. proton electron shells neutron Write concise definitions for these
words
shells
neutron

2. 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

3. Atomic Structure – Inside the Atom
There are three types of particle inside the atom – protons, neutrons and electrons
An atom of lithium
Protons
Neutrons
Electrons

4. Atomic Structure – Inside the Atom
The sub-atomic particles have different charges and masses
Particle
Charge
Mass
(in atomic units)
Proton 1+ 1
Neutron
Electron 1-

5. Atomic number = number of protons
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.

6. 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

7. 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 C 12 14 6 6
Carbon-12
Carbon-14
Write down the number of protons, neutrons and electrons in the two isotopes of carbon

8. 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…

9. H H H Hydrogen exists as 3 isotopes…
although Hydrogen-1 makes up the vast
majority of the naturally occurring element. H 1 H 2 1 H 3 1
Protons
Electrons
Neutrons
Hydrogen
Protons
Electrons
Neutrons
(Deuterium)
Protons
Electrons
Neutrons
(Tritium)
All have a different mass, tritium is radioactive but all react with oxygen to form water

10. Which of the following is not a sub-atomic particle?
Proton.
Isotope.
Neutron.
Electron.

11. 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?
It contains 59 neutrons.
It contains 27 electrons.
It contains 32 protons.
It contains equal numbers of neutrons and electrons.

12. contains more protons than neutrons.
The Periodic Table displays iron as shown below. This indicates that Fe atoms:
contain 56 neutrons.
contain 30 electrons.
contain 26 protons.
contains more protons than neutrons. 56 Fe 26

13. Which of the following is true: Both isotopes contain 35 protons.
Bromine consists of a mixture of two isotopes: Bromine-79 and Bromine-81
Which of the following is true:
Both isotopes contain 35 protons.
Bromine 79 contains 46 neutrons.
Bromine 81 contains 44 neutrons.
Bromine-81 is more reactive than bromine-79. 80 Br 35

14. Natural boron consists of approx. 20% boron-10 and 80% boron-11.
What will the relative atomic mass of natural boron will be?
10.0
11.0
10.5
10.8 ? B 5

15. Which answer best describes the shell arrangement of the electrons in a sodium atom?
2,8,1.
2,2,7.
2,8,8,3.
2,8,8,1. 23 Na 11

16. Which answer best describes the shell arrangement of the electrons in an oxygen atom?
2,8,6.
2,8,8.
2,8.
2,6. 16 O 8

17. Which of these elements will have electron shells that are either full or empty (i.e. not partially full)? 14 N 7 A 40 Ar 18 B 40 Ca 20 C 27 Al 13 D

18. Which answer best describes the shell arrangement of the electrons in an oxide ion O2-?
2,8,6.
2,8.
2,8,8.
2,6. 16 O 8