Question

As we move from left to right in a period, which of the periodic properties decreases?
This question can have multiple answers.
A.Electronegativity
B.Atomic size
C.Electropositivity
D.Metallic character

Answer 1

Before answering this question, we should first know what are periodic trends. Periodic trends are patterns that are specified in the chemical properties of elements given in the periodic table. The characteristics include electronegativity, electropositivity, ionization energy, electron affinity, atomic radii, ionic radii, metallic character, and chemical reactivity.

Complete answer:
When we move from left to right across a period, the chemical reactivity of elements decreases and then increases. The number of valence electrons increases from 1 to 8 when we move from left to right across a period. The atomic size decreases on moving from left to right in a period. There is a decrease in the size of an atom.
Due to the decrease in the size of an atom, the electronegativity increases when we move across the period whereas when we go down the group, the atomic size increases which result in the decrease in the electronegativity down the group, and Electropositivity is the reverse of electronegativity so electropositivity decreases across the period. It a metallic attribute, So Alkali metals are considered the most electropositive elements.
Due to the increase in the electronegativity across the period, All the atoms are more capable to accept the electrons rather than losing them to eliminate an unfilled shell. So, the Metallic character decreases when we move across a period.

So, Option (B) Atomic size
Option (C) Electropositivity
Option (D) metallic character
are correct.

Note:
The difference between Electronegativity and Electropositivity –
The ability of an atom to attract a shared pair of bonded electrons is electronegativity. Non-metals have high electronegativities compared to Metals.
The ability of an atom to donate electrons to form positively charged elements is electropositivity. Metallic elements have electropositivity.