Chemistry - Atomic Structure & the Periodic Table

Compare the plum pudding model with the modern nuclear model. (4)

● Both models contain electrons

● Both are neutral overall

● The plum pudding model has no nucleus/protons/neutrons

● The nuclear model has energy levels

Define the term isotopes. Refer to subatomic particles in your answer. (2)

● Atoms with the same number of protons

● With different numbers of neutrons

Describe the plum pudding model of the atom. (2)

● A ball of positive charge

● Negative electrons embedded

Atoms contain electrons, neutrons and protons. Write these three particles in order of their discovery. (1)

1. Electrons

2. Protons

3. Neutrons

Tennessine was first identified by a small group of scientists in 2010. Suggest one reason why tennessine was not accepted as a new element by other scientists until 2015. (1)

Peer review

Suggest what would happen to the temperature of water as it flows through a condenser. (1)

Increases

Describe how to obtain sodium chloride crystals from sodium chloride solution by crystallisation. (2)

● Heat the solution until crystallisation point is reached

● Leave the solution to crytallise

Argon has the atomic number 18. Explain why argon does not form compounds. Answer in terms of electrons. (2)

● Argon has a stable arrangement of electrons

● They don’t share electrons

Suggest two observations that could be made when barium reacts with hydrochloric acid. (2)

● Bubbling

● Barium disappears

Predict one observation you would see that shows that rubidium is more reactive than potassium. (1)

More vigorous bubbling

Explain why rubidium is more reactive than potassium. (3)

● Rubidium’s outer shell is further from the nucleus.

● There is less electrostatic attraction between the nucleus and the outer electron

● The outer electron is more easily lost

Give two reasons why the discovery of gallium helped Mendeleev’s periodic table to become accepted. (2)

● It fitted in a gap Mendeleev had left

● It’s properties were predicted correctly