Unit 2 Flashcards
Periodic Table
What does the property of an element depend on?
Atomic number (protons)
How is the periodic table arranged?
In atomic numbers
How many electrons does each orbital hold?
S P D F
2
6
10
14
What does a period tell you?
Energy level. (number of shells)
What does group tell you?
Number of valence electrons
Trends in atomic radius
↓← Decrease across a period is due to more protons meaning more attraction
Increase down a group is due to shielding
What is ionisation energy?
Amount of energy needed to remove an electron from an atom in gas phase
Trend in ionisation energy?
↑→ increases across a period as more protons and no increased shielding.
Decreases down a group as shielding increases
What is metallic character?
How readily an atom can lose an electron. So highly electronegative elements (eg) fluorine have very little metallic character
Trend in metallic character?
↓← (opposite of ionisation) more shielding less attraction to the nucleus
Properties of metals?
Good electric and heat conductors. Malleable Solid at room temp Lose valence shells easily Reducing agent
Non metal properties
Poor electric and heat conductors brittle many forms at room temp Gain valence shells Oxidizing agent
what is a hydride?
Compound formed by hydrogen and another element only
What are covalent hydrides?
H+ Non- metal
What are ionic hydrides?
H+ metal
What are metallic hydrides?
h+ transition metal
What is an oxide?
An oxygen and another element only
What are acidic oxides?
Oxides of non metals. Also known as acid anhydrides
What are basic oxides?
Oxides of group 1 and 2 aka base anhydrides
What is an amphoteric solution?
Can act as both an acid or a base
What is an amphoteric oxide?
A metallic oxide that shows both acidic and basic properties
What is a diagonal relationship?
The fact that metallic character increases down a group and decreases across a period means they cancel out diagonally. Meaning diagonal elements can have similar properties.
What element has the highest ionisation energy?
Helium. i.E increases up a group and across a period
Is high electronegativity a characteristic of metals or non metals?
Non metals
Is oxidising ability a property of metals or non metals
Non metals
is being a poor electrical conductor a property of metals or non metals?
Non metals
Is being opaque when thin a characteristic of metals or non metals?
Metals
Are ionic hydrides soluble?
No
What are metallic hydrides also known as?
Interstitial hydrides
Explain the trend in boiling points
looking at periods 2 and 3 the boiling point increases until C and si .
This is because they have giant metallic structures. and the nuclear charge is getting bigger so increased attraction meaning harder to separate them.
C and Si are giant covalently bonded so have even higher.
Melting points drop and N and P b/c simple covalent bonds aren’t as strong, so don’t need as much energy. Mr also affects these, heavier means more van der waals