Topic 6 : Groups in the Periodic Table Flashcards
(30 cards)
What is the name for Group 1 elements?
Alkali Metals.
What are the alkali metals?
Lithium, Sodium, Potassium, Rubidium, Caesium and Francium
What ions do alkali metals form
Form 1+ ions.
Why are alkali metals so reactive?
They only need to lose 1 electron to become stable, so less energy is required to do this.
What is the trend as you go down Group 1?
Melting and boiling points decrease and reactivity increases as you go down.
Why are alkali metals more reactive as you go down the group and therefore have a lower melting and boiling points?
As you go down Group 1 the outer electron is lost more easily as more electron shells → further from nucleus → less strongly attracted to nuclues → easier to lose electron.
What alkali metal can spontaneously react at room temperature?
Caesium
How do alkali metals react with water and what is formed?
Alkali metals react vigorously with water to form a metal hydroxide and hydrogen gas.
E.g. Sodium + Water → Sodium Hydroxide + Hydrogen
2Na + 2H2O →2NaOH + H2
How do alkali metals reactions with water change as you go down the group?
Lithium → move around surface and furiously fizz.
Sodium → do the same but also melt in reaction heat.
Potassium → even gets hot enough to ignite the produced hydrogen.
Rubidium + Caesium → tend to explode when they get wet.
What are the properties of alkali metals
Soft, low density, low melting point, reactive
Why do alkali metals have similar properties?
Alkali metals exhibit similar properties as they are all in Group 1 and have one electron in their outermost shell - they react similarly.
What is the name for Group 7 elements?
Halogens.
What are the halogens?
Fluorine, Chlorine, Bromine,Iodine and Astatine
What type of molecules do halogens exist as?
Diatomic molecules - share a pair of electrons in a covalent bond.
Why do halogens have similar properties?
Halogens have similar chemical properties as they are all in Group 7 and have seven electrons in their outermost shell - they react similarly.
Can you describe the halogens at room temperature?
Fluorine: very reactive poisonous pale gas.
Chlorine: less reactive poisonous green gas.
Bromine: reddy brown poisonous liquid + gives off orange vapour.
Iodine: dark grey solid that can form poisonous purple vapours.
How do halides react with metals
React vigorously with metals to form salts called metal halides.
How do halogens react with hydrogen
React to form hydrogen halides which are soluble and can dissolve in water to form acidic solutions e.g. HCl forms hydrochloric acid in water.
Why does reactivity decrease as you go down Group 7?
Halogen only needs to attract 1 electron to form a 1- with a stable electronic structure. Outer shell further from nucleus (larger atomic radius) → weaker attraction → harder to attract electrons
Why does melting and boiling point increase as you go down Group 7?
Atoms increase in size → more electron shells → stronger intermolecular forces → for enrgy needed to break bonds.
What ions do halogens form?
They form 1- ions
How do displacement reations show the reactivity trend of the halogens?
The higher the halogen is in Group 7 the more halogens it displaces during reaction and so the more reactive it is.
What waters and solutions are used in the halogen displacement reactions test?
chlorine water, bromine water and iodine water react with potassium chloride, potassium bromide and potassium iodide. They solution stays colourless if no reaction occurs or turns orange or brown and forms the displaced element as well.
e.g. Chlorine water + potassium bromide→ Potassium chloride + Bromine
Cl2 + 2KBr → 2KCl + Br2
What is the name for Group 0 elements?
Noble Gases.
