Topic 4 - Groups in the Periodic Table Flashcards
What are most of the elements in the periodic table?
Metals
Where are the metals on the periodic table?
Everywhere apart from the far right
Where are the transition metals?
The middle block
What are some of the properties of metals?
- Conduct electricity well
- Malleable (bent or hammered into different shapes)
What are some uses of metals based on their properties?
- Electrical wires (electrical conductivity)
- Bridges/car bodies (malleable)
What are some of the properties of transition metals?
- High melting points
- Form colourful compounds (use in hair dyes, colour in gemstones, colours in pottery glazes)
How are metals structured?
Regular arrangement of atoms held together with metallic bonds
- Metallic bonds give metal giant structure of +ve ions + free electrons as metallic bonds allow outer electrons of each atom to become delocalised
- Creates sea of delocalised electrons (hence metal’s electrical conductivity)
- Giant metallic structure = high melting/boiling points + are insoluble
- Allow layers of atoms to slide over each other so can be bent/shaped (hence malleability)
Where are the alkali metals on the periodic table?
Group 1
What are the properties of the alkali metals?
- Soft (can be cut w/ a knife)
- Low melting points compared to other metals
How do the Group 1 elements react with water?
- Lithium, sodium or potassium react vigorously to form hydroxides
- Makes an alkaline solutions (hence alkali metals)
Why do the elements in Group 1 get more reactive as the atomic number increases?
Have more electrons so more electrons shells so further from nucleus so less attraction between negative electrons + positive nucleus
What does the reaction between an alkali metal and water produce?
-Hydrogen (what you see fizzing)
Alkali metal + water –> alkaline solutions [hydroxide] + hydrogen
How do you test for hydrogen?
A lighted splint will squeak if hydrogen is present
Which Group are the halogens?
7
What are the properties of chlorine (halogen) at room temperature?
- Fairly reactive
- Poisonous
- Dense green gas
What are the properties of bromine (halogen) at room temperature?
- Dense
- Poisonous
- Orange liquid
What are the properties of iodine (halogen) at room temperature?
Dark grey crystalline solid
What is the general word equation of the reaction between a metal and a halogen?
Metal + halogen –> metal halide
What is the general equation for the reaction between a halogen and hydrogen?
Halogen + hydrogen –> hydrogen halide
What is a property of hydrogen halides?
Soluble - dissolve in water to form acidic solutions
How do halogens displace each other?
- Higher in Group 7 = more reactive as outer shell nearer nucleus so pull of +ve nucleus = greater to electrons
- Halide dissolves in water so halide ions free to react
- More reactive halogen reacts w/ solution containing halide ions pushing out less reactive
- This is a displacement reaction
- e.g. Cl~2(g) + 2KI(aq) –> I~2(aq) + 2KCl(aq)
What group are the noble gases?
0
What are the properties of the noble gases?
- Colourless gas at room temp
- Inert (don’t react much) as have full outer shell
- Non flammable
How were the noble gases discovered?
- Chemists noticed density of nitrogen made in chemical reactions different to density of nitrogen taken from air
- Hypothesised nitrogen from air must have other gases
- Discovered them by experiments incl. fractional distillation of air
