The periodic table
4 marks · NormalThe symbol for silver in the periodic table shows:
Use this information to answer the following questions about a silver atom.
State the mass number of this silver atom.
State the atomic number of this silver atom.
Calculate the number of neutrons in this atom.
State the number of electrons in a neutral atom of silver.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) 107
(b) 47
(c) 60
(d) 47
Common mistakes: Subtracting wrong way round; Using incorrect number for atomic/mass number
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Mass number given as 107
B2 (b) · 1 mark · Atomic number given as 47
M1 (c) · 1 mark · Number of neutrons calculated correctly (107 - 47 = 60) (follow-through)
B3 (d) · 1 mark · Number of electrons given as 47
Worked solution
(a) The mass number is the larger number, so it is 107.
(b) The atomic number is the smaller number, so it is 47.
(c) Number of neutrons = mass number - atomic number = 107 - 47 = 60
(d) For a neutral atom, the number of electrons equals the atomic number, so there are 47 electrons.