1 - Atomic Structure

Question 1

What are the elements in Group 1?

Answer 1

Alkali metals

Question 2

What are the elements in Group 2?

Answer 2

Alkaline earth metals

Question 3

What are the elements in the Middle section?

Answer 3

Transition metals

Question 4

What are the elements along the Staircase?

Answer 4

Metalloids

Question 5

What are the elements in Group 7?

Answer 5

Halogens

Question 6

What are the elements in Group 8?

Answer 6

Noble gases

Question 7

What is the law of the conservation of mass?

Answer 7

The total mass of products formed in a reaction is equal to the total mass of the reactants.

Question 8

What are the features of a compound?

Answer 8

• fixed ratio
• joined & separated by chemical reactions
• have chemical bonds between atoms

Question 9

What are the features of a mixture?

Answer 9

• no fixed composition
• created & separated by physical means
• no chemical bonds between atoms

Question 10

What does filtration separate?

Answer 10

Insoluble substances from soluble ones.

Question 11

What does crystallisation separate?

Answer 11

A pure sample of salt from a salt solution by heating & evaporation.

Question 12

What does distillation separate?

Answer 12

A solvent from a solute by heating and evaporating off the liquid to be condensed.

Question 13

What are miscible and immiscible liquids?

Answer 13

Miscible liquids dissolve in eachother and mix completely, whereas immiscible liquids form separate layers & settle over eachother.

Question 14

How can you separate miscible liquids?

Answer 14

Evaporate and condense the liquid with a lower boiling point first.

Question 15

What is fractional distillation?

Answer 15

When liquids have similar boiling points, you use a fractionating column to pass vapours between the glass beads. The substance with a higher boiling point will condense at the bottom and drip back down & the substance with a lower boiling point will continue to rise.

Question 16

How can you test if an ethanol and water mixture has been fully distilled?

Answer 16

Apply a lighted splint to the mixtures - ethanol is flammable except when mixed with excess water.

Question 17

What is paper chromatography?

Answer 17

Paper chromatography separates mixtures of substances dissolved in a solvent as they move up the chromatography paper.

Question 18

What is the history of the atom?

Answer 18

1. John Dalton - atoms were tiny hard spheres that could not be divided or split
2. J.J. Thomson discovered the electron when applying high voltages to gases at low pressures - beams of particles were attracted to positive charge = they were negatively charged. He proposed that electrons were embedded in positive mass.
3. Geiger & Marsden - Alpha particles experiment. Discovered that electrons orbit the nucleus, containing protons.
4. Niels Bohr - Discovered energy levels/shells on atoms.
5. Evidence of the neutron was explained by ‘missing mass’

Question 19

What is the atomic number?

Answer 19

No. of protons (also no. of electrons)

Question 20

What is the mass number?

Answer 20

No. of protons + neutrons

Question 21

What are isotopes?

Answer 21

Atoms of the same element with different numbers of neutrons.

Question 22

Why are the physical properties of isotopes different but the chemical properties are the same?

Answer 22

Isotopes have different physical properties such as density or radioactivity however, their chemical properties stay the same because their reactions with other elements depend on the electronic structure of their outer shell.