Topic 6 - Groups in the Periodic Table Flashcards
Why can some elements be classified by their positions in the periodic table?
Elements in the same group (column) have similar characteristics because they have the same amount of valence electrons in their outermost shells
What are group 1 elements known as?
Alkali metals
Are alkali metals soft, averagely hard, or hard?
Soft
Do alkali metals have relatively high or low melting and boiling points?
Low (compared with other metals)
Describe the reactions of lithium, sodium and potassium with water
Each reaction produces hydrogen gas and a hydroxide of the respective metal.
The lithium moves around the surface, fizzing furiously.
The sodium moves around the surface, fizzing furiously, melting in the heat of the reaction.
The potassium moves around the surface, fizzing furiously, melting in the heat of the reaction. It gets hot enough to ignite the hydrogen gas being produced.
Order potassium, lithium and sodium based on their positions in the periodic table, from top to bottom
lithium, sodium, potasium
What is the relationship between an element’s position in group 1 and it’s reactivity with water? Why?
The reactivity of the group 1 metals with water increases down the group because the valence electron, as it moves further away from the attracting force of the nucleus (as there are more electron rings in the atom), is lost more easily in the reaction
What are group 7 elements known as?
Halogens
What are the colour and physical state of chlorine at room temperature?
A (fairly reactive, poisonous) green gas
What are the colour and physical state of bromine at room temperature?
A (poisonous) red-brown liquid which gives off an orange vapour at room temperature
What are the colour and physical state of iodine at room temperature?
A dark-grey crystalline solid which gives off a purple vapour when heated
