IONIC BONDING [dchemlc]

which of the following ions do not have noble gas structures?

• Ru⁺

• I^-

• Fe²⁺

• Be²⁺

Answer explanation

for the first 20 elements, atoms lose or gain electrons so that they achieve noble gas configuration.

however their are a lot of common ions which dont have noble gas structures.

e.g. Fe²⁺, Fe³⁺, Cu²⁺, Zn²⁺, Ag⁺, Pb²⁺

which of the following statements is not true about ionic compounds?

• Ionic compounds have high melting points and boiling points

• Ionic compounds tend to be crystalline

• Ionic substances tend to be soluble in water.

• Ionic compounds tend to be soluble in organic solvents.

Answer explanation

THE PHYSICAL PROPERTIES OF IONIC SUBSTANCES

# Ionic compounds have high melting points and boiling points.

# Ionic compounds tend to be crystalline.

# Ionic crystals tend to be brittle.

# Ionic substances tend to be soluble in water.

# Ionic compounds tend to be insoluble in organic solvents.

Ionic compounds don't conduct electricity when they are solid but they do conduct electricity when they are molten or in aqueous solutions. What is the reason for this?

• because the ions are fixed in position and are not free to move around.

• because the electrons are fixed in position and are not free to move around.

• beacause the molecules do not have neough energy to move around

• because the ionic compound is not soluble in water

Answer explanation

Ionic compounds don't conduct electricity when they are solid because the ions are fixed in position and are not free to move around. They do, however, conduct electricity when they are molten or in aqueous solution. This happens because the ions then become free to move around. Do not use the word 'electrons'. You must talk about the ions being free to move.

which of the following ionic compounds would have the higher melting point?

• KCl

• CaO

Answer explanation

A lot of energy has to be supplied to break the strong electrostatic forces of attraction between oppositely charged ions in the giant lattice structure.

CaO has a higher melting point than KCl because in CaO, 2+ ions are attracting 2- ions. In KCl, the electrostatic attractions are weaker because they are only between 1 + and 1- ions.

what will be the charge of group 5 non-metals when they turn into ions?

• -3

• -2

• 3

• 2

Answer explanation

Any element in Group 2 has 2 outer electrons, which it will lose to form a 2+ ion. Any element in Group 6 has 6 outer electrons, and it has room to gain 2 more; this leads to a 2- ion. Similar arguments apply in the other groups.

what is the charge of the carbonate ion?

• -2

• -1

• 2

• 1

Answer explanation

How many of these do you know?😎

what is the charge of Iron(III) ion in Fe₂O₃?

• 3

• 2

• -3

• -2

Answer explanation

All metals form positive ions. Names such as lead(II) oxide, iron(III) chloride or copper(II) sulfate tell you directly about the charge on the metal ion. The number after the metal tells you the number of charges, so:

• lead(II) oxide contains a Pb²⁺ ion

• iron(III) chloride contains an fe³⁺ ion

which of the following correctly depicts the formula of copper(II) sulphate?

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• 

Answer explanation

Don't confuse ions such as sulfate and sulfide. A name like copper(II) sulfide means that it contains copper and sulfur only.

Once you have an 'ate' ending, it means that there is oxygen (and possibly other things) there as well.

You have to be careful using the swapping method. Copper (II) sulfate is CuSO₄ and not Cu₂(SO₄)_2.

which of the following gives the correct formula of ammonium nitrate?

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Answer explanation

FUN FACT 😃

ammonium nitrate is commonly used as a fertilizer.

which of the following diagrams correctly depicts the dot and cross diagrams of magnesium combining with chlorine?

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Answer explanation