1.1) Atomic Structure and the Periodic table - EXAM QUESTIONS

Question 1

Mendeleev’s table became accepted by other scientists whereas Newlands’ table
was not.
Evaluate Newlands’ and Mendeleev’s tables.
You should include:
* a comparison of the tables
* reasons why Mendeleev’s table was more acceptable.
Use Figure 2 and Figure 3 and your own knowledge
(6 MARKS)

Answer 1

• both tables have more than one element in a box
• both have similar elements in the same column
• Newlands did not leave gaps for undiscovered elements
• Mendeleev left gaps for undiscovered elements
• Mendeleev predicted properties of missing elements
• elements with properties predicted by Mendeleev were
  discovered

Question 2

The formula of potassium chromate is K2CrO4
The charge on the potassium ion is +1
What is the formula of the chromate ion?

Answer 2

CrO42–

Question 3

The Plum pudding Model did not have a nucleus.
Describe three other differences between the nuclear model of the atom and the plum plum pudding model.
(3 MARKS)

Answer 3

• Mostly empty space
• Positive charge is in the nucleus
• Mass is concentrated in the nucleus

Question 4

Niels Bohr adapted the nuclear model.
Describe the change that Bohr made to the nuclear model.
(2 MARKS)

Answer 4

• electrons orbit the nucleus
• electrons are at specific distances from the
  nucleus

Question 5

Mendeleev published his periodic table in 1869.
Mendeleev arranged the elements in order of atomic weight.
Mendeleev then reversed the order of some pairs of elements.
A student suggested Mendeleev’s reason for reversing the order was to arrange
the elements in order of atomic number.
Explain why the student’s suggestion cannot be correct. Use Figure 2.
(2 MARKS)

Answer 5

• atomic number is the number of
  protons
  -(and) protons were not
  discovered until later

Question 6

Give the correct reason why Mendeleev reversed the order of some pairs of elements.
(1 MARK)

Answer 6

so their properties matched the
rest of the group

Question 7

Explain how.
(4 MARKS)

Answer 7

• most (alpha) particles passed (straight)
  through (the gold foil)
• (so) most of the atom is empty space
• some (alpha) particles were deflected /
  reflected
• (so) the atom has a (positively) charged
  nucleus / centre

Question 8

Answer :
(1 MARK)

Answer 8

include a (filter) funnel

Question 9

Answer:
(3 MARKS)

Answer 9

• Chadwick provided the evidence to show the
  existence of neutrons
• (this was necessary because) isotopes have the
  same number of protons
• but with different numbers of neutrons

Question 10

Answer:
(1 MARK)

Answer 10

has three electrons in outer energy level / shell

Question 11

Answer:
(6 MARKS)

Answer 11

Physical
Transition elements
* high melting points
* high densities
* strong
* hard
Group 1
* low melting points
* low densities
* soft
__________________________________________________Chemical
Transition elements
* low reactivity / react slowly (with water or oxygen)
* used as catalysts
* ions with different charges
* coloured compounds
Group 1
* very reactive / react (quickly) with water / non-metals
* not used as catalysts
* white / colorless compounds
* only forms a +1 ion

Question 12

Answer:
(3 MARKS)

Answer 12

• too many electrons in the first energy level or
  inner shell
• too few electrons in the second energy level or
  outer shell
• neon does not have 9 electrons or neon has 10
  electrons

Question 13

Answer:
(4 MARKS)

Answer 13

• sodium (atom) loses
• fluorine (atom) gains
• one electron
• ions formed