Topic 6- Groups In The Periodic Table Flashcards
Where are the alkali metals found on the periodic table ?
Elements found in Group 1 (found on the left-hand side of the periodic table)
How many outer shell electrons does an alkali metal have ?
Their outer shell has 1 electron in it, which is usually given away in chemical reactions
What is lithium’s electron configuration (structure) ?
Lithium has the electron structure (2,1).
What is the least reactive if the alkali metals ?
Lithium is the least reactive of the alkali metals
When lithium burns with oxygen what is the colour of the flame ?
Lithium burns with a crimson flame when it reacts with oxygen.
What will be released when lithium floats in the surface of water ?
Lithium floats on the surface of water and will release bubbles of hydrogen gas (it effervesces)
What is sodium’s electron configuration (structure) ?
Sodium has the electron structure (2,8,1).
Why is sodium more reactive than lithium?
Sodium is more reactive than lithium because its outer electron is less strongly attracted to the positively charged nucleus. This is because it is a greater distance from the positive charge of the atom’s nucleus.
What colour is the flame when sodium reacts with oxygen ?
Sodium burns with a yellow/orange flame when it reacts with oxygen.
What happens when sodium is on the surface of water ?
The metal floats on the surface of water, which releases enough heat to melt the sodium. The sodium moves quickly across the surface of the water.
What is the electron configuration (structure) of potassium ?
Potassium has the electron structure (2,8,8,1).
Why is potassium more reactive than lithium and sodium ?
Potassium is more reactive than lithium and sodium because its outer electron is least strongly attracted to the nucleus.
What is the colour of the flame when potassium reacts with oxygen?
Potassium burns with a lilac flame when it reacts with oxygen
What happens when potassium floats on the surface of water ?
The metal floats on the surface of water, and has a similar, but more vigorous, reaction compared with sodium
What do all group 1 (and 2) elements end with?
ium
Lithium
Potassium
Sodium
What are the properties of alkali metals (group 1) ?
All of the elements in Group 1 have 1 electron in their outer shell.
These metals are very reactive because they easily lose the electron in their outer shell.
All react with:
Chlorine
Water
Oxygen
What happens when a metal alkali reacts with chlorine ?
A metal chloride is formed (e.g. sodium chloride), which dissolves in water to give a colourless solution
What happens when an alkali metal reacts with water ?
The metal floats on the surface and melts to create a metal hydroxide (e.g. lithium hydroxide).
When they react with water, the energy released is enough to melt the metal.
What happens when an alkali metal reacts with oxygen ?
Rapidly turns from silvery shiny to dull as a metal oxide (e.g. potassium oxide) is produced
As you move down group 1 of the periodic table, the reactions of alkali metals become quicker and more vigorous. Why is this ?
Distance - The number of electron shells increases meaning there is a greater distance between the outer electron and the nucleus
Strength of attraction - The greater the distance between the outer electron and the nucleus, the weaker the attraction between them
Reactivity - The weaker the attraction between the outer electron and the nucleus, the easier it is for the outer electron to be lost
What do Potassium, sodium and lithium all react quickly with cold water to produce what ?
a metal hydroxide and hydrogen gas
What happens when potassium reacts with cold water ?
Potassium is the most reactive so reacts very quickly.
The hydrogen produced ignites instantly and the metal also sets alight, sparking and burning with a lilac flame
What happens when sodium reacts with cold water ?
Sodium fizzes rapidly and melts to form a ball that moves around on the water surface.
What happens when lithium reacts with cold water ?
Lithium fizzes steadily and floats, becoming smaller until it eventually disappears
As you go down the group, the reactions become quicker and more vigorous. Why is this ?
Electron shells - The atoms gain more electron shells as you go down group 1.
This means there are more electron shells in between the nucleus and outer electron, which shields the electron from the nuclear charge.
This means that the electron is more easily lost, so the atom is more reactive.
Weaker attraction - The attraction between the positive nucleus and negative outer electron becomes weaker as you go down the group because the outer electron is further from the nucleus.
Metal + water —> ? + ?
Metal + water —> metal hydroxide + hydrogen
What are Elements in group 7 of the periodic table called ?
Elements in group 7 in the periodic table are called halogens
How many outer shell electrons do group 7 elements (halogens) have ?
They have 7 electrons in their outer shell
Why are group 7 elements (halogens) very reactive ?
They are very reactive because they easily accept an electron into this outer shell.
They have similar properties and react in similar ways.