Elements of Life

Question 1

What is the mass and charge of a proton, neutron and electron?

Answer 1

Proton: mass 1, charge +1.
Neutron: mass 1, charge 0.
Electron: mass negligible, charge -1.

Question 2

Describe absorption spectra.

Answer 2

Particles absorb emitted radiation, any analysed light is missing certain frequencies, these line appear black.

Question 3

Describe emission spectra.

Answer 3

Particles absorbing energy are raised to higher energy states. These particles lose energy by emitting radiation. These are coloured lines on a black background.

Question 4

Define atomic spectra.

Answer 4

Hydrogen and helium atoms are seen on an emission spectrum. The emissions and absorptions match up.

Question 5

Describe Bohr’s Theory.

Answer 5

The electron in hydrogen only exists in certain energy levels.
A photon is emitted when an electron changes energy level.
Energy of a photon is equal to the difference between two energy levels.

Question 6

What are the flame tests for Lithium, Sodium, Potassium, Calcium, Barium and Copper.

Answer 6

Li+ red
Na+ yellow
K+ lilac
Ca2+ brick red
Ba2+ green
Cu2+ blue green

Question 7

Describe an s subshell.

Answer 7

One s orbital, two electrons.

Question 8

Describe a p subshell.

Answer 8

Three p orbitals, six electrons.

Question 9

Describe a d subshell.

Answer 9

Five d orbitals, ten electrons.

Question 10

Describe an f subshell.

Answer 10

Seven f orbitals, fourteen electrons.

Question 11

Describe the trends in period 3.

Answer 11

Melting and boiling points increase up to Phosphorus, where they drop.

Question 12

Define covalent bonding.

Answer 12

Two non-metals sharing electrons.

Question 13

Define dative covalent bonds.

Answer 13

Both bonding electrons come from the same atom.

Question 14

What is the bond angle in a linear molecule?

Answer 14

180°.

Question 15

What is the bond angle in a planar molecule?

Answer 15

120°.

Question 16

What is the bond angle in a bipyramidal molecule?

Answer 16

90° and 120°.

Question 17

What is the bond angle in an octahedral molecule?

Answer 17

90°.

Question 18

What is the bond angle in a tetrahedral molecule?

Answer 18

109.5°.

Question 19

How many degrees does a lone pair remove?

Answer 19

2.5°.

Question 20

Which ionic substances are insoluble?

Answer 20

Barium, calcium, lead and silver sulfates.
Silver and lead halides.
All metal carbonates.
Metal hydroxides except Group 1 and ammonium.

Question 21

What colour precipitates are formed when sodium hydroxide is added to Cu2+, Fe2+ and Fe3+?

Answer 21

Cu2+ blue.
Fe2+ green.
Fe3+ brown.

Question 22

What colour precipitate is formed when potassium iodide is added to Pb2+

Answer 22

Pb2+ yellow.

Question 23

What colour precipitates are formed when silver nitrate is added to Cl-, Br-, and I-.

Answer 23

Cl- white.
Br- cream.
I- yellow.

Question 24

What colour precipitate is formed when barium chloride is added to SO4^2-?

Answer 24

SO4^2- white.

Question 25

Describe ionic bonding.

Answer 25

Metal and a non metal transferring electrons.

Question 26

Describe group 1 and 2 trends.

Answer 26

More metallic down a group, less metallic across a period.

Question 27

Describe ionisation enthalpy.

Answer 27

X(g) > X+(g) + e-.

Across a period, more atomic shielding but more protons increasing the nuclear charge.
Down a group, more atomic shielding.

Question 28

Describe Group 2 reactions with oxygen, water, heat and hydroxides.

Answer 28

Oxygen: produces the metal oxide.
Water: forms metal hydroxide and hydrogen. Increase in reactivity down the group.
Heat: metal oxide and carbon dioxide. Thermal stability increases down the group.
Hydroxides: react with acids to make salts.

Question 29

Define charge density.

Answer 29

Concentration of the charge on cation.