UNIT 1 PPQ Flashcards
(19 cards)
Discuss why potassium and argon aren’t in order of increasing mass
The periodic table has the events arranged by increasing number of protons (1)
The atomic masses are due to protons and neutrons (1)
In argon there are more atoms with greater number of neutrons (1)
Why are bonds polar
Molecules are polar if their atoms have different electronegativities (1)
Or
In a covalent bond, where electrons are not shared equally
Describe an element as it travels through a MASS SPEC
Describe the structure of diamond and graphite and state one physical property of them which is similar for both and then one difference.
each carbon atom in diamond has four (strong) covalent bonds in tetrahedral structure (1)
each carbon atom in graphite has three (strong) covalent bonds forming hexagons in planes (1)
both have high melting points (1)
due to giant molecular structure of strong covalent bonds (1)
graphite conducts electricity but diamond does not (1)
because graphite has delocalised electrons along the planes (1)
Write an equation to show the first ionisation energy
X(g) ——-> X+ (g) + e-
(1)
Explain why first ionisation energies increase on value from left to right?
Increasing number of protons present in the nucleus therefore greater nucleus charge (1)
Greater attraction therefore more energy is needed to removed electron (1)
[2]
When dilute sulphuric acid is added to magnesium chloride and barium chloride, only barium chloride is observed to have a white ppt.
Include an equation in your explanation
Ppt of barium sulphate forms with barium chloride.
Ba2+ + SO4^2- —-> BaSO4 (s)
Doesn’t form a ppt with magnesium chloride as magnesium sulphate is appreciably soluble.
[3]
Street lights contains sodium vapour emit yellow light.
Electrons are excited but electricity
Promoted to a higher enegy level
Fall back to a lower energy level and give out energy
The energy emitted is in the yellow part of Visibile spectrum.
Explain why silicon oxide is a solid with a very high melting temperature whereas silicon chloride is a liquid at room temperature.
SiCl4 is a simple covalent molecule with weak intermolecular forces therefore easier to break.
SiO2 is a giant covalent molecule which has strong covalent bonds which need to be broken to melt SiO2
Why are mixtures filtered
To remove solid impurities aq
Why does ice float on water
Ice is LESS dense than water (1)
Ice has a hydrogen bonded lattice (1)
Which is partially broken in water (1)
Explain the chlorine mass spec
2 isomers Cl35 and Cl37 in a 3:1 ratio.
70,72,74. 3 peaks in a 9:6:1 ratio.
Explain the bromine mass spec
Why are magnesium and barium described as s block elements
Have outer electrons in s block
What is meant by electronegativity
Ability of an atom to attract an electrons in a covalent bond
Why cant you form Ba3+ ions
Why is magnesium ductile
Bonding consists of metal ions surrounded by a sea of delocalised electrons. (1)
There is an electrostatic attraction between the ions and electrons (1)
When a force is applied the layers of metals slide over each other forming a new shape. (1)
What does the limit represent
Ionisation of the atom
