Electrotechnology engineering

Models of the Atom

Q1 (3 marks TOTAL):
(a) Describe Rutherford’s nuclear model of the atom. Use a diagram to show what Rutherford’s model consisted of. (2 marks)

(b) Explain the main flaw (problem) with Rutherford’s model. (1 mark)

Q2 (4 marks TOTAL):
(a) Describe Bohr’s nuclear model of the atom. (1 mark)

(b) Explain why Bohr’s model overcame the main flaw with Rutherford’s model.
(1 mark)

(c) Using Bohr’s model of the atom, explain why fluorescent materials appear bright.
(2 marks)

Atomic Number and Element Sizes

Q3 (3 marks TOTAL):
(a) Define what the Atomic Number is for an element. (1 mark)

(b) Define what the Mass Number is for an element. (1 mark)

(c) An element has an Atomic Number = 20 and Mass Number = 44. (1 mark)
Use the Periodic Table of Elements to identify what this element is.

Q4 (5 marks TOTAL):
(a) Explain why Potassium has a lager atomic size than Lithium (1 mark)

(b) Explain why Scandium has a smaller atomic size than Potassium even though it has
more protons. (2 marks)

(c) Explain why anions are twice the size of the parent atom and yet cations are only half the size of parent atom. (2 marks)

Groups in the Periodic Table

Q5 (9 marks TOTAL):
(a) Write below the name of the Group 1 (or IA) elements in the Periodic Table (1 mark)

(b) Explain why these elements are very reactive. (1 mark)

(c) What types of ions are formed by Group 1 elements? Anions or Cations?
Justify your answer with a reason. (1 mark)

(d) In which Group do the Noble Gases belong? (1 mark)

(e) Explain why the Noble Gases are very non-reactive (inert). (1 mark)

(f) In which Group does the element Ge belong? (1 mark)

(g) What is the main use for Ge? (1 mark)

(h) In which Group does Cl belong? (1 mark)

(i) List one use for Cl. (1 mark)

Compound Bonding

Q6 (6 marks TOTAL)

(a) Explain what Covalent Bonding is in a compound. (1 mark)

(b) Use an electron dot diagram to show how covalent bonding occurs in the CO2 molecule (1 mark)

(c) Explain what Ionic Bonding is in a compound. (1 mark)

(d) Use a diagram to show how the salt NaCl is formed using Ionic bonding. (1 mark)

(e) Is the compound HCl a Covalent bonded or Ionic bonded molecule? (2 marks)
Justify your answer with a reason.

Metals

Q7 (4 marks TOTAL)

(a) Explain how Bonding occurs in Metals. Use a diagram to show how electrons are arranged in metals. (2 marks)

(b) Explain how the bonding in a metal allows for metals to be very malleable (1 mark)

(c) Explain how bonding in a metal allows for metals to be good electrical conductors(1 mark)

Valency Q8 (5 marks TOTAL)

(a) Explain what is Valency. (1 mark)

Using Cation & Anion Valency Tables write chemical formula for the following compounds:

(b) Silver chloride (1 mark)

(c) Potassium Carbonate (1 mark)

(d) Calcium Phosphate (2 marks)

Chemical Reactions

Q9 (8 marks TOTAL)

(a) Explain the difference between an exothermic and endothermic reaction (1 mark)

(b) Describe what the “Law of Conservation of Mass” is. (1 mark)

(c) Write the balanced chemical reaction for the combustion of zinc in oxygen. (2 marks)
(Hint: Use the valency table from the lesson notes)

(d) Explain what a Decomposition chemical reaction is. (1 mark)

Re-write the following chemical reactions as balanced equations:

(e) CH4 + O2 → CO2 + H20 (1 mark)

(f) Al2O3 + HCl → AlCl3 + H2O (2 marks)

Last Updated on February 11, 2019 by EssayPro