Chemistry 2a Topics 1, 2 & 3

Question 1

The element boron has 5 protons. How many electrons does a boron atom have in its outer shell?

Answer 1

3

Question 2

Potassium has 19 protons. Work out its electronic configuration

Answer 2

2, 8, 8, 1

Question 3

Name the three types of particles in an atom

Answer 3

Proton, neutron & electron

Question 4

Is it the number of protons or the number of neutrons that decides what element an atom is

Answer 4

The number of protons

Question 5

What do the mass number and atomic number represent?

Answer 5

Mass number: total number of protons and neutrons

Atomic number: number of protons

Question 6

What is relative atomic mass?

Answer 6

This is the average mass of the different forms of an element

Question 7

Explain how Mendeleev arranged known elements in a table. How did he predict new elements?

Answer 7

He arranged them based on their properties and the properties of their compounds. He predicted new elements because he realised there were gaps

Question 8

“elements in the modern periodic table are in order of atomic number.” True or false?

Answer 8

True

Question 9

What are columns in the periodic table called?

Answer 9

Periods

Question 10

What happens to the electrons when two atoms form an ionic bond?

Answer 10

They either lose or gain electrons

Question 11

Are cations positive or negative ions?

Answer 11

Positive

Question 12

List the main properties of ionic compounds

Answer 12

They have high melting points and high boiling points

Question 13

Name two insoluble chlorides

Answer 13

Silver chloride and lead chloride

Question 14

Explain why barium sulfate can be drunk even though it’s toxic

Answer 14

because it is insoluble therefore it cannot enter the blood

Question 15

In a flame test, a metal gives a blue-green flame. Name the metal.

Answer 15

Copper

Question 16

How would you test for sulfate ions in a solution?

Answer 16

Tot test for sulfate ions in a solution, add dilute hydrochloric acid, then add barium solution

Question 17

Give two elements that were discovered by spectroscopy

Answer 17

Rubidium and caesium

Question 18

What is a covalent bond?

Answer 18

A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms

Question 19

What are the two types of covalent substance?

Answer 19

Hydrogen and water

Question 20

Kerosene and water are immiscible. Describe how you could separate a mixture of these two liquids.

Answer 20

Shake together, let them stand so they separate out into layers, use a separating funnel with a tap to separate the layers then the tap can be opened to drain of the lower layer into a beaker

Question 21

Liquid air is a mixture of miscible liquids. Name e method that can be used so separate them.

Answer 21

Fractional distillation