Ionic compounds and analysis

Question 1

what does a atom have the same number of, does it have a overall charge

Answer 1

same number of protons and electrons, no overall charge because charges are balanced by protons and electrons

Question 2

how does a atom become a ion

Answer 2

by gaining or losing one or more electrons.

Question 3

does a ion have a charge

Answer 3

yes, because it no longer has the same number of protons and electrons.

Question 4

when metals lose electrons what do they form

Answer 4

positively charged cations

Question 5

metals in groups 1, 2, and 3 lose how many electrons? and to from ions with what charge?

Answer 5

> group 1 lose 1 electron with a 1+ charge
group 2 lose 2 electrons with a 2+ charge
group 3 lose 3 electrons with a 3+ charge

Question 6

non-metals gain electrons to form what

Answer 6

negatively charged anions

Question 7

non-metals in groups 5, 6, 7 lose how many electrons? and to from ions with what charge?

Answer 7

> group 5 gain 3 electrons with a 3- charge
group 6 gain 2 electrons with a 2- charge
group 7 gain 1 electrons with a 1- charge

Question 8

perform dot and cross diagrams for ionic bonding

Answer 8

s

Question 9

what is an ionic compound formed from a non-metal and a metal called

Answer 9

a salt

Question 10

how do you find the formula of a given compound fro compound ions aswell, do examples

Answer 10

swan and drop method

Question 11

what type of melting and boiling points do ionic substances have and why

Answer 11

high melting and boiling points because the ions are held together in the lattice by very strong electrostatic forces. a lot of energy is needed to break these bonds. ionic substances are solid at room temp and have to be heated strongly to melt them

Question 12

give the relation of conducting electricity to ionic substances

Answer 12

ionic substance s do not conduct electricity when they are solid because the ions are held together in a lattice. they do conduct electricity when they are molten or dissolved in water because the charged particles can move around

Question 13

which ionic substances are soluble in water

Answer 13

> sodium carbonate, potassium carbonate, ammonium carbonate
sodium hydroxide, potassium hydroxide, ammonium hydroxide
all nitrates
most chlorides ( except silver chloride and lead chloride)
most sulfates (except lead sulfate, barium sulfate, and calcium sulfate)

Question 14

what is a precipitate

Answer 14

when two soluble substances form a insoluble solid

Question 15

how can we prepare insoluble salts using precipitation reactions

Answer 15

1) mix solutions of two substances that will form the insoluble salt
2) filter the mixture. the insoluble salt will be trapped in the filter paper.
3) was the salt with pure paper.
4) leave the salt to dry on the filter paper. it could be dried in an oven

Question 16

what is barium sulfate

Answer 16

it is a insoluble salt

Question 17

give uses of barium sulfate

Answer 17

is given as a barium meal to patients who are going to have their stomachs or intestines x-rayed because:
> barium sulfate is opaque to x-rays. so it shows up well on the x-ray picture
> it is safe to use ( because it is barium sulfate it does not get into the blood

Question 18

describe flame tests and the colours given off by each metal ion

Answer 18

some metal ions can be identified using flame tests. a damp splint is placed in the solid and then held in a Bunsen burner flame. the colour of the flame identifies the ion.
> sodium = yellow
> potassium = lilac
> calcium = red
> copper = green-blue

Question 19

describe how a spectroscope was used to discover new elements.

Answer 19

very small amounts of some elements can be detected in flame tests by using a spectroscope. the elements rubidium and caesium were discovered when scientists spotted colours in parts of the spectrum they had not seen before

Question 20

describe carbonate ions test and results

Answer 20

test: add dilute acid to the substance. test the gas given off with limewater
results: if the subsatcne contains carbonate ions, it will fizz or bubble as a gas is given off, the gas will turn limewater milky, showing the gas is carbon dioxide

Question 21

describe sulfate ions test and results

Answer 21

test: add a few drops of dilute hydrochloric acid. shake the mixture. add a few drops of barium chloride solution
results: if the substance contains sulfate ions, a white precipitate of barium sulfate forms

Question 22

describe chloride ions test and results

Answer 22

test: add a few drops of dilute nitric acid to the solution. shake the mixture, add a few drops of silver nitrate solution.
results: if the substance contains chloride ions, a white precipitate of silver chloride forms