C1 Atoms (Part 4) Flashcards
Elements that react to form
positive ions are…?
Metals
Elements that do not form
positive ions are…?
Non-metals
Elements in Group 1 are known as…?
The alkali metals
State three characteristics of the Alkali Metals
All have one electron in their outer shell
They have low density
They are stored under oil (to prevent reactions with oxygen or water)
They are soft (can be cut with a knife).
How do Group 1 elements react with non-metals?
Why are these reactions similar for the different Group 1 elements?
They form ionic compounds which are soluble white solids that form colourless solutions – they all have one electron in their outer shell.
How do Group 1 elements react with water?
They release hydrogen and form hydroxides which dissolve to form alkaline solutions
They react vigorously with water fizzing and moving around on the surface of the water.
How does the reactivity change moving down Group 1? Why?
Reactivity increases as the atoms get larger and the distance between the nucleus and the outer electrons increases and thus attraction from the nucleus decreases, allowing them to more easily lose electrons.
State five CHARACTERISTICS of Group 7
- 7 electrons in outer shell
- Coloured vapours
- Diatomic molecules
- Form ionic salts with metals
- Form molecular compounds with non-metals
State Group 7 elements and their states of matter.
Fluorine, (F. F2) - pale yellow gas. Chlorine, Cl. Cl2 - pale green gas. Bromine, Br. Br2 - dark brown liquid Iodine, I. I2 - grey solid.
State three changes that occur in Group 7 as one moves down the group
- Higher relative molecular mass
- Higher melting and boiling point
- Less reactive – harder to gain electron due to outer shell far away
A more reactive halogen displaces a less reactive one from an aqueous solution of its salt
Write the equations and state the colour change seen when:
- chlorine reacts with sodium bromide
Cl2 + 2 NaBr → Br2 + 2 NaCl
In this reaction, an orange colour of Br2 would appear
A more reactive halogen displaces a less reactive one from an aqueous solution of its salt
Write the equations and state the colour change seen when:
- chlorine/bromine reacts with sodium iodide.
Cl2 + 2 NaI → I2 + 2 NaCl
Br2 + 2 NaI → I2 + 2 NaBr
In these two reactions, a brown colour of I2 would appear
A more reactive halogen displaces a less reactive one from an aqueous solution of its salt.
Explain the trend in reactivity of halogens in these reactions.
Reactivity decreases down the group.
As we go down the group, the atoms get larger, so an incoming electron will be less tightly held by the attractive forces from the nucleus.
That’s why Cl displaces Br– and I–
