Module 10

1
Module 10

• Atoms Isotopes

2
Learn

• recall that all atoms of the same element have
  the same number of protons
• recall the relative charges and relative masses
  of protons, neutrons and electrons
• understand the terms atomic number and mass number

3
Learn

• understand that isotopes are atoms of the same
  elements with the same number of protons and
  electrons, but different numbers of neutrons
•  
• calculate the relative atomic mass of an element
  from relative masses and abundances of its
  isotopes

4
recall that all atoms of the same element have
the same number of protons

• Atoms contain protons,neutrons and electrons.
• An atom is defined by the number of protons that
  it has. e.g. All Carbon atoms have 6 protons that
  is what makes carbon carbon. If carbon had 7
  protons it would be nitrogen.

5
recall the relative charges and relative masses
of protons, neutrons and electrons
6
understand the terms atomic number and mass
number

• The atomic number of an element tells you the
  number of protons in an atom. (This usually is
  the same as the number of electrons.)
• The mass number is the number of protons the
  number of neutrons of an atom.

7
understand that isotopes are atoms of the same
elements with the same number of protons and
electrons, but different numbers of neutrons

• Isotopes are atoms of the same element but with a
  different number of neutrons.
• e.g. Carbon 12 is an isotopes of carbon
• So is
• e.g. Carbon 14 is an isotopes of carbon
• Most isotopes behave similarly to each other in
  chemical reactions.

8
calculate the relative atomic mass of an element
from relative masses and abundances of its
isotopes

• In many A level text books the atomic mass of
  chlorine is quoted as 35.5!
• How can this be we cannot have half a proton or
  neutron?
• The figure of 35.5 is given because chlorine is
  made up of about 75 Chlorine-35 and about 25
  Chlorine-37.