Question 25
On moving from left to right in a period in the periodic table, the size of the atom.

(a) increases
(b) decreases
(c) does not change appreciably
(d) first decreases and then increases

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Solution

Option (b) is correct.
In a period, the size of an atom decreases from left to right. This is because of the nuclear charge, that is, the atomic number increases from left to right in the same period, thereby bringing the electrons closer to the nucleus.

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Similar questions

Q. On moving from left to right in a period of the periodic table, the atomic number of elements increases. What happens to the size of atoms of elements on moving from left to right in a period?

(a) increases
(b) decreases
(c) remain the same
(d) first increases then decreases

Q. In the periodic table of the elements in a period from left to right atomic radius increases or decreases?

Question 48 (c)
(a) Electropositive nature of the element(s) increases down the group and decreases across the period
(b) Electronegativity of the element decreases down the group and increases across the period
(c) Atomic size increases down the group and decreases across a period (left to right)
(d) Metallic character increases down the group and decreases across a period.
On the basis of the above trends of the Periodic Table, answer the following about the elements with atomic numbers 3 to 9.

Name the element with smallest atomic size.

Q. Part (i) to (v) refer to changes in the properties of elements on moving from left to right across a period of the periodic table. For each property, choose the letter corresponding to the correct answer from the choices (a), (b), (c) and (d).
(i) The non-metallic character of the elements:
(a) decreases
(b) increases
(c) remains the same
(d) depends on the period

(ii) The electronegativity:
(a) depends on the number of valence electrons
(b) remains the same
(c) decreases
(d) increases

(iii) The ionisation potential:
(a) goes up and down
(b) decreases
(c) increases
(d) remains the same

(iv) The atomic size:
(a) decreases
(b) increases
(c) remains the same
(d) sometimes increases and sometimes decreases

(v) The electron affinity of the elements in groups 1 to 7:
(a) goes up and then down
(b) decreases and then increases
(c) increases
(d) decreases

Q. Assertion :Atomic size decreases in a period due to increase of atomic number. Reason: The nuclear charge is increasing and size of valence shell remains same as we move from left to right. Hence, in any period, the atomic size of the element decreases from left to right.

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Periods in Modern Periodic Table

Standard IX Chemistry

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Question 25 On moving from left to right in a period in the periodic table, the size of the atom. (a) increases (b) decreases (c) does not change appreciably (d) first decreases and then increases

Option (b) is correct. In a period, the size of an atom decreases from left to right. This is because of the nuclear charge, that is, the atomic number increases from left to right in the same period, thereby bringing the electrons closer to the nucleus.

Question 25
On moving from left to right in a period in the periodic table, the size of the atom.

(a) increases
(b) decreases
(c) does not change appreciably
(d) first decreases and then increases

Option (b) is correct.
In a period, the size of an atom decreases from left to right. This is because of the nuclear charge, that is, the atomic number increases from left to right in the same period, thereby bringing the electrons closer to the nucleus.