Question
Question: In period \(2\), element A is to the right of element B. Compare the following properties of A and B...
In period 2, element A is to the right of element B. Compare the following properties of A and B
A) The element A would probably have a [smaller/larger] atomic size than B.
B) The element A would probably have a [lower/higher] ionization potential than A.
C) The element A would have [lesser/higher] electron affinity than B.
D) Nuclear charge of element B would be [less/more] than element A.
E) If an element C had low electronegativity and ionization potential it would have more tendency to [gain/lose] electrons.
Solution
We know that across a period, the number of electrons increases from left to right. We also know that the atomic size of an element depends on the number of electrons present in it. As the electrons increase, the effective nuclear charge also increases.
Complete step-by-step answer: A) As we move from left to right across a period, the number of electrons and neutrons increase. This means that the effective nuclear charge increases. So the electrons are closer to the nucleus. Hence the size of the atom decreases accordingly.
Hence, element A would probably have a smaller atomic size than B.
B) If the nuclear charge of an atom is more, the electrons are strongly attracted to the nucleus making it hard to remove an electron. This means that more energy will be required for atoms with high nuclear charge. We have already noted that the nuclear charge increases across the period and hence ionization potential also increases.
Hence, element A would probably have a higher ionization potential than B.
C) Across the period, the atomic size decreases and hence the atoms are closer to nucleus , exposing them to more nuclear attractions.
Hence, element A would have higher electron affinity than B.
D) Nuclear charge increases across the period due to the increase in electrons and neutrons.
Hence, the nuclear charge of element B would be less that element A.
E) If an element C has less electronegativity and ionization potential then it must be on the left of elements A and B and hence its electron affinity would be lesser.
Hence, the tendency of element C to lose electrons is more than A and B.
Note: Important points to be remembered: Atomic size decreases across the period, Ionization potential increases across the period, electron affinity increases across the period and nuclear charge increases across the period.