Answer:
Mercury and helium
1034.8575
Explanation:
Given that :
Melting point of substances :
Nickel: 2,651
Mercury: -37.89
Helium: -458
Copper: 1,984.32
Melting means change of solid to liquid
a) Which two elements have melting points that are closest in value?
The difference in Melting point between mercury and helium :
- 37.89 - (-458) = 420.11
Nickel and copper :
2651 - 1,984.32 = 666.68
Hence, element with melting point which are closest in value Are Mercury and helium
b) What is the average melting point of the substances?
Sum of the melting points / number of substances
(2,651 + (-37.89) + (-458) + 1,984.32) / 4
= 4139.43 / 4
= 1034.8575