1. Two particles having the same numbers of protons and neutrons but different number of electrons might be an atom and
A an ion of different elements.
B an ion of same element.
C an isotope of different elements.
D an isotope of the same element.
2. Why are the elements sodium and chlorine in the same Period of the Periodic Table?
A Sodium is a reactive metal and chlorine is a reactive non-metal.
B Sodium and chlorine combine together to form a compound of formula
C The atoms of both elements have only three electron shells containing
D The atoms of both elements have eight electrons in their second
3. The formulae of the ions of some elements are shown below.
N3- O2- F– Li+ Mg2+
Which statement about these ions is CORRECT? They all have
A the same number of electrons in their outermost shells.
B the same electronic structure as a noble gas.
C the same number of neutrons in their nuclei.
D more electrons than protons.
4. In which one of the following sets do all 3 particles have the same total number of electrons?
A CI─, Br─, I─
B F─, Ne, Na+
C H─, H, H+
D S2-, SO3, SO32-