The periodic table- group 7 ( halogens )

what are the group 7 elements known as

halogens

what is the formula of the halogens

F2

Cl2

Br2

I2

what is the formula of the halide ions

F-

Cl-

Br-

I-

name the halogens

fluorine

chlorine

bromine

iodine

group 7 elements are all what molecules

diatomic ( contain 2 atoms )

name the halide ions

fluoride

chloride

bromide

iodide

what is the colour and physical state of fluorine at room temperature?

pale yellow

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gas

what is the colour and physical state of chlorine at room temperature?

pale green

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gas

what is the colour and physical state of bromine at room temperature?

dark red

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liquid

what is the colour and physical state of iodine at room temperature?

shiny grey

solid

what is the colour of fluorine vapour

yellow

what is the colour of chlorine vapour

green

what is the colour of bromine vapour

orange

what is the colour of iodine vapour

purple

how do the boiling points change as you go down group 7

they get higher

what is the colour of the halogens when they are dissolved in water

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1. chlorine solution
2. bromine solution
3. iodine solution

1. pale green
2. orange
3. brown

what is the charge on group 7 elements in ionic compounds and why

1- charge (negative )

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gain one electron when they react to from a full outer shell

what colour is sodium chloride

colourless

anything that’s has -ide is colourless

write a balanced chemical equation for this reaction

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chlorine + sodium bromide → sodium chloride + bromide

Cl2 + 2NaBr → 2NaCl + Br2

1. write a word equation for this reaction

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chorine reacting with sodium bromide

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2. what are the formulas of the products?

1. chlorine + sodium bromide → sodium chloride + bromine

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2. NaCl + Br2

what what the colour change in this equation

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1. chlorine + sodium bromide → sodium chloride + bromine

pale green → orange

write a balance chemical equation for this reaction

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chlorine + sodium iodide → sodium chloride + iodine

Cl2 + 2NaI → 2NaCl + I2

1. write a word equation for this reaction

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chlorine reacting with sodium iodide

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2. what are the formulas of the products

1. chlorine + sodium iodide → sodium chloride + iodine

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2. NaCl + I2

what was the colour change in this equation?

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chlorine + sodium iodide → sodium chloride + iodine

pale green → brown

write a balanced chemical equation for this reaction

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bromine + sodium iodide → sodium bromide + iodine

Br2 + 2NaI → 2NaBr + I2

1. write a word equation for this reaction

bromine reacting with sodium iodide

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2. what are the formulas of the products

1. bromine + sodium iodide → sodium bromide + iodine

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2. NaBr + I2

what was the colour change for this reaction

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bromine + sodium iodide → sodium bromide + iodine

orange → brown

what happens to the reactivity as you go down group 7 and why?

the reactivity decreases- become less reactive

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* as you go down the group, the element has more electron shells in its structure
* e.g chlorine has more electron shells than fluorine
* therefore the electron it is gaining is further away from the nucleus meaning its less attracted
* and the electron isn’t gained as easily

testing for halide ions using silver nitrate- method

* place four test tubes in a rack containing 2cm death of these solution

sodium chloride solution

sodium bromide solution

sodium iodide solution

solution containing ‘mystery’ halide ion

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* place 0.5cm3 of silver nitrate solution into each test tube using a pipette
* observe the colour of the precipitate that is formed
* if its white- chloride
* if its cream- bromide
* if its yellow- iodide
* record results in table
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what is formed when a halide ion reacts with silver nitrate

coloured precipitate ( solid )

word equation for testing for the halide ion chloride using silver nitrate

sodium chloride + silver nitrate → silver chloride + sodium nitrate

what is a chemical equation?

balanced symbol equation

what is the chemical equation for when silver nitrate reacts with sodium chloride to test for the halide ion chloride

AgNO3 + NaCl → AgCl + NaNO3

what is the chemical equation for when silver nitrate reacts with sodium bromide to test for the halide ion bromide

AgNO3 + NaBr → AgBr + NaNO3

word equation for testing for the halide ion bromide using silver nitrate

silver nitrate + sodium bromide → silver bromide + sodium nitrate

what is the chemical equation for when silver nitrate reacts with sodium iodide to test for the halide ion iodide

AgNO3 + NaI → AgI + NaNO3

word equation for testing for the halide ion iodide using silver nitrate

silver nitrate + sodium iodide → silver iodide + sodium nitrate

What is the trend in melting points of the halogens

As you go down the group, they get higher

what colour of precipitate is formed when sodium chloride reacts with silver nitrate

white

what is formed when sodium chloride/ bromide/ iodide react with silver nitrate

precipitate

what colour of precipitate is formed when sodium iodide reacts with silver nitrate

yellow

what colour of precipitate is formed when sodium bromide reacts with silver nitrate

cream