Paper 2 · Atomic structure, metallic and ionic bonding, dot-and-cross diagram
Element E has an electron arrangement of 2,8,7 across its three shells. What is the number of protons in atom E?
A17
B16
C18
D7
Explanation: The total number of electrons (and therefore protons in a neutral atom) equals the sum of electrons in all shells: 2 + 8 + 7 = 17.
Derived from ZIMSEC Chemistry 4024/2 Paper 2 Theory, November 2018, Q1
