Groups Of The Periodic Table 🧨 Flashcards
What group of the periodic table are the alkali metals?
Group 1
List two properties of alkali metals?
- Relatively low melting points
- Soft
Why are group 1 elements called the alkali metals?
They react with water to form alkaline solutions (pH greater than 7)
Why should alkali metals be stored in oil?
To prevent them reacting with water vapour and oxygen in the air.
What should be observed when lithium reacts with water?
- Slowest reaction of the alkali metals.
- Bubbles of hydrogen are produced.
- Doesn’t melt (highest melting point of alkali metals)
What would be observed when sodium reacts with water?
- Faster reaction than lithium.
- Floats on the surface of water
- Bubbles of hydrogen are produced which cause sodium to whizz around the surface of the water.
- Melts as enough energy is given out to meet sodium’s melting point.
What would be observed when potassium reacts with water?
- More violent reaction than sodium.
- Bubbles of hydrogen are produced which cause the potassium to whizz around the surface of the water.
- Melts into a shiny ball.
- Burns with a lilac flame.
What is the order of reactivity of the first three alkali metals with water?
Lithium reacts least violently, potassium reacts most violently:
Lithium < Sodium < Potassium
Reactivity trend down group 1.
Reactivity increases down group 1.
What group are the halogens? Why?
Group 7 because they have 7 outer shell electrons.
What colour and state of chlorine at room temp?
Pale green gas
What colour and states of bromine at room temp?
Red-brown liquid
What colour and state is iodine at room temp?
Black solid
Why does melting point and boiling point increase going down group 7?
The molecules get bigger down the group so there are more intermolecular forces to overcome during melting / boiling so more energy is required.
Describe the trend in reactivity of the halogens. How does this affect the rate of reaction?
Reactivity decreases going down group 7.
Rate of the reaction decreases down group 7.
