Topic 2 - Ionic Compounds and Analysis Flashcards by Adam Harward

What is ionic bonding?

When atoms transfer (lose or gain) electrons to form charged (+vley or -vely) atoms (/group of atoms) called ions. As opposite charges attract, the ions are strongly attracted to one another

How well did you know this?

Not at all

Perfectly

Why do atoms transfer electrons?

To try to get a full outer shell

How well did you know this?

Not at all

Perfectly

How do sodium and chlorine bond together?

Sodium atom gives outer electrons to chlorine (Na+, Cl-)

- Opposite charges attract so attracted together as ionic bond

How well did you know this?

Not at all

Perfectly

What Groups’ atoms most readily form ions?

1, 2, 6, 7

How well did you know this?

Not at all

Perfectly

How do Group 1 + 2 elements form ions?

Lose electrons
Positively charged ions
Cations

How well did you know this?

Not at all

Perfectly

How do Group 6 + 7 elements form ions?

Gain electrons
Negatively charged ion
Anions

How well did you know this?

Not at all

Perfectly

What charge do anions have?

Negative

How well did you know this?

Not at all

Perfectly

What charge do cations have?

Positive

How well did you know this?

Not at all

Perfectly

On the periodic table, where do two elements have to be to form ionic bonds with one another?

On opposite ends of the periodic table

How well did you know this?

Not at all

Perfectly

How does magnesium and oxygen form an ionic bond?

Magnesium gives 2 outer electrons (Mg2+)
Oxygen takes electrons (O2-) (oxide ion)
Forms MgO, magnesium oxide

How well did you know this?

Not at all

Perfectly

How does sodium and oxygen form an ionic bond?

2 sodium give outer electron (2xna2+)
Oxygen takes 2 electrons (O2-)
Na2O

How well did you know this?

Not at all

Perfectly

How does calcium and chlorine form an ionic bond?

Calcium transfers 2 outer electrons (1 to each chlorine: Ca2+, 2x Cl-)
CaCl2

How well did you know this?

Not at all

Perfectly

What kind of structures do ionic compounds have?

Regular lattice

How well did you know this?

Not at all

Perfectly

How does an ionic regular lattice form?

Ions form closely packed regular lattice arrangement
Due to ionic bonds having strong electrostatic forces of attraction between oppositely charged ions
Ionic compounds all have similar properties because of their structrue

How well did you know this?

Not at all

Perfectly

What are the properties of an ionic compound?

High melting point
High boiling point
Conduct electricity when aqueous or molten

How well did you know this?

Not at all

Perfectly

Why do ionic compounds have high melting points and high boiling points?

Due to the very strong bonds between the ions

- Takes a lot of energy to break these bonds

Why do ionic compounds conduct electricity when aqueous or molten?

Ions are separate + free to move so carry electric current

- Ions are held rigid in solid so aren’t free to move so can’t conduct electricity

What are the two rules when naming a compound?

When 2 different elements combine compound’s name is ‘something -IDE’
When 3 or more different elements combine + 1 is oxygen, compound’s name is ‘something -ATE’

What is the solubility rule for common salts of sodium, potassium and ammonium?

Soluble (-carbonates, hydroxides)

Which salts of sodium, potassium and ammonium are insoluble?

Carbonates and hydroxides

What is the solubility rule for all nitrates?

Soluble

What is the solubility rule for common chlorides?

Soluble (-silver, lead)

Which chloride salts are insoluble?

Silver chloride + lead chloride

What is the solubility rule for common sulfates?

Soluble (-lead, barium, ammonium)

Which sulfate salts are insoluble?

Lead sulfate, barium sulfate + calcium chloride

What is the solubility rule for common carbonates and hydroxides?

Insoluble (-sodium, potassium, ammonium)

How do you make a pure, dry sample of an insoluble salt by a precipitate reaction?

-Precipitation reaction: pick 2 soluble salts + react together -E.g. lead chloride: lead nitrate + sodium chloride (both soluble) Method: 1) - 1 spatula Pb(NO3)2 to test tube + fill w/ distilled water. Shake thoroughly so all dissolves. Same w/ NaCl (dist. water ensures no other ions) -Tip 2 solution into small beaker, stir so all mixes. PbCl should precipitate out 2) - Put filter paper into filter funnel, into conical flask -Pour contents through -Swill out beaker w/ dist. water, tip into beaker (ensures all product from beaker) 3) - Rinse all contents of filter paper w/ dist. water so all soluble sodium nitrate is washed away -Scrape lead chloride onto fresh filter paper + leave to dry

How could you make a pure, dry sample of barium sulfate (BaSO4), an insoluble salt?

- Mix solution of barium 'something' + 'something' sulfate (as long as both soluble, e.g. barium nitrate + potassium sulfate) - Filter out precipitate of barium sulfate - Wash w/ dist. water (remove impurities) - Dry on filter paper

How can barium sulfate be used for X-rays?

- Normally, only bones show in X-rays - Barium sulfate is opaque to X-rays; when drunk shows up gut so any problems i.e. blockages can be seen - Barium salts are toxic, but barium sulfate can be drunk safely as insoluble, so isn't absorbed into bloodstream, just passes though body - When patient drinks barium sulfate before X-ray, known as barium meal

What colour flame do sodium ions (Na+) produce in the flame test?

Yellow/orange flame

What colour flame do potassium ions (K+) produce in the flame test?

Lilac flame

What colour flame do calcium ions (Ca2+) produce in the flame test?

Brick-red flame

What colour flame do copper ions (Cu2+) produce in the flame test?

Blue-green flame

How would you do a flame test in a lab?

- Dip clean wire loop into sample of compound + put into clear blue part of Bunsen flame (hottest part) - Make sure wire loop is really clean by dipping into HCl + rinsing with dist. water

How do you test for carbonates (CO3 [2-])?

-React carbonate w/ dilute acid -Bubble gas produced through limewater, as if carbonate, CO2 released which turn limewater cloudy acid+carbonate-->salt+water+carbon dioxide

How do you test for sulfate ions (SO4 [2-])?

-Add dilute HCl, followed by barium chloride, BaCl2 -White precipitate of barium sulfate means original compound was a sulfate Ba[2+](aq) + SO4 [2-] (aq) --> BaSO4 (s}

How do you test for chloride ions (Cl-)?

-Add dilute nitric acid (HNO3), then silver nitrate solution (AgNO3) -Chloride give white precipitate of silver chloride Ag[+](aq) + Cl[-](aq) --> AgCl(s)

How can spectroscopy be used to identify elements?

- Patterns of light emitted by elements in a heated sample are analysed - Each element present in sample produces different colours - Spectroscopy is fast + reliable + can be used to detect even small amounts of elements in a sample - Allowed scientists to discover new elements e.g. rubidium + caesium, both discovered as produced patterns of light not seen before