c) atomic structure

Question 1

1.9- understand that atoms consist of a central nucleus, composed of protons and neutrons, surrounded by electrons, orbiting in shells.

Answer 1

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Question 2

1.10- recall the relative mass and relative charge of a proton, neutron and electron

Answer 2

Electrons- 1/1840 = -1 = e
Protons- 1 = +1 = p
Neutrons- 1 = 0 = n

Question 3

1.11- understand the terms; atomic number, mass number, isotopes and relative atomic mass (Ar)

Answer 3

Atomic number- number of protons in an atom

Mass number- total number of protons and neutrons

Isotopes- atoms of the same element with different neutron numbers

relative atomic mass- weighed average mass of the isotopes of the element.

Question 4

1.12 calculate the relative atomic mass of an element from the relative abundances of its isotopes

Answer 4

Calculate the relative formula mass of the compound with the formula: H2SO4
Answer
(H = 1, S = 32, O = 16)
  H2SO4
  (2 x H)  (1 x S)  (4 x O)
  (2 x 1)  (1 x 32)  (4 x 16)
  2    32    64
  2 + 32 + 64 = 98

Question 5

1.13 understand that the periodic table is an arrangement of elements in order of atomic number

Answer 5

Periodic Table is an arrangement of elements in order of atomic numbers. It consists of 8 groups and 7 periods.

Question 6

1.14- How to work out electronic configuration?

Answer 6

Electronic configuration can be easily figured out by following few rules:

1st shell must contain only two electrons
2nd shell must contain only 8 electrons
3rd shell must contain only 8 electrons
4th shell must contain only 18 electrons

· Atomic number is equal to electrons in an “atom”

Example:

Na(Sodium) : 2,8,1

Ca(Calcium): 2,8,8,2

Question 7

1.15- deduce the number of outer electrons in a main group element from its position in the Periodic Table.

Answer 7

The group number determines outer electron of an element.

Example:

Group I elements have 1 electrons in their outer shell

Group 7 elements have 7

Group 0 have 8(since 8 comes after 7)- they have a full outer shell.