The Periodic Table Flashcards
What is the periodic table?
The periodic table is a table that arranges the elements in a unique arrangement.
Where (roughly) are the metals found?
On the left (roughly)
Where (roughly) are the non-metals found?
On the far right
What are periods in the periodic table?
The rows (horizontal)
What are groups in the periodic table?
Columns (vertical), the elements in the same group usually have similar properties.
Characteristics of Alkali Metals
- Soft
- Melt at a lower temperature than most metals
- Highly reactive (and muse be stored under oil)
Which group are the Alkali Metals in?
Group 1
Alkali metal reaction with water?
They react vigorously with water. The chemical formula is:
_______ + water → _______ hydroxide + hydrogen
What is the trend in reactivity with the Alkali Metals?
The reactions become more vigorous as you descend down the group.
For example, Lithium’s (Li) reaction with water can be seen as just a small amount of effervescence, whereas Francium’s (Fr) reaction causes a very dangerous explosion.
What are the properties of metals?
- Shiny
- High melting points
- Good conductors of electricity
- Good conductors of heat
- High density
- Malleable (can be hammered/pressed into a new shape without breaking)
What are the properties of non-metals?
- Dull
- Low melting points
- Poor conductors of electricity
- Poor conductors of heat
- Low density
- Brittle (easily broken)
How to test for hydrogen in an alkali metal + water?
Using a lit splint:
1. Fill up a test tube partially with water.
2. Place a freshly cut portion of an alkali metal in the water.
3. Place a little splint over the test tube, and if you hear a squeaky pop then hydrogen is present.
What are the Group 1 Alkali Metals?
- Lithium (Li)
- Sodium (Na)
- Potassium (K)
- Rubidium (Rb)
- Caesium (Cs)
- Francium (Fr)
Lithium (Li) observations
- Appearance: Black, dull (non-shiny) solid
- Appearance when freshly cut: Shiny, grey, solid, soft
- Hardness: Soft
- Observations with water: effervescence, hydrogen gas burning → smoke, vigorous
- When universal indicator is added: blue → purple
- Lit splint test: squeaky pop, ignite
- Products: lithium hydroxide and hydrogen
Sodium (Na) observations
- Appearance: White, solid
- Appearance when freshly cut: Shiny, soft
- Hardness: Softer than Li
- Observations with water: Melted into a ball → hot, hydrogen gas burning → smoke, heated, more vigorous
- When universal indicator is added: Leaves a purple trail (sodium) when more [sodium] is added
- Lit splint test: squeaky pop, ignite
- Products: sodium hydroxide and hydrogen
Potassium (K) observations
- Appearance: Grey, solid
- Appearance when freshly cut: Shiny, soft
- Hardness: Softer than Na
- Observations with water: Lilac flame, hydrogen gas burning → lots of smoke, heated, most vigorous
- Ignition: Lilac flame
- When universal indicator is added: blue → purple
- Lit splint test: squeaky pop, ignite
- Products: potassium hydroxide and hydrogen
Calcium (Ca) reaction with water
- Effervescence
- A white precipitate (solid) is formed
- Smoke
- Not dissolved
What are the group 2 elements called?
The Alkaline Earth Metals
Names of the alkaline earth metals
- Beryllium (Be)
- Magnesium (Mg)
- Calcium (Ca)
- Strontium (Sr)
- Barium (Ba)
- Radium (Ra)
Magnesium added to water
- slight effervescence only visible when extremely close up
- forms magnesium hydroxide + hydrogen
Calcium added to water
- white precipitate
- effervescence
- smoke
- not dissolved fully
- forms calcium hydroxide + hydrogen
Strontium added to water
- effervescence
- smoke
- forms strontium hydroxide + hydrogen
What is the trend in reactivity with the Alkaline Earth Metals?
More reactive as you go down the group.
Which is more reactive, Alkali Metals or Alkaline Earth Metals?
Alkali Metals
What are the Group 7 elements and what are their properties?
The Halogens (they are non-metals and are diatomic elements)
Fluorine properties
- pale yellow gas
- used to make some plastics and toothpaste
Chlorine properties
- pale Green gas
- used in bleach
Bromine
- dark red liquid
- used in fire retardants
Iodine properties
- grey solid
- antiseptics in hospital procedures
What is a diatomic molecule?
An element that can only exist on its own as 2 atoms, unless as a compound with another element.
Halogen + metal →
Metal halide
(e.g. bromine + iron → iron bromide)
Test for water
Add copper sulphate, and if it turns blue (when usually white) water is present.
Test for carbon dioxide
- add a lint split to the gas inquisition and if that lit splint becomes extinguished, then we know there is carbon dioxide present
This is because the carbon dioxide displaces oxygen and therefore prevents combustion
Word equation for combustion
Hydrocarbon + oxygen → carbon dioxide + water
Uses of hydrocarbons
- fuel
- synthetic fabrics
- plastics
- power generation
