Which sets of elements have similar chemical and physical properties? 1. Mg and Ra 2. Al and P 3. Be and Ba 4. Na and Cl

1 & 2 ,

2 & 3

1 & 3

2 & 4

1 & 3

Explanation:

Elements have similar chemical and physical properties if and only if they belong to the same group of elements in the periodic table.

A group of elements in the periodic table is a family of elements, the elements in the in the same group have the same number of valence electrons in their outermost shell, share similar chemical reactivity (with slight variation within the group) and similar physical properties  (with slight variation within the group).

Magnesium, radium, beryllium and barium all belong to group 2 hence they have similar chemical and physical properties.

pure substance: iron,copper

impure substance: water,charcoal

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.