Question

question 9 of 10
what makes the atomic radius change along a period in the periodic table?
a. more electrons in the valence shell make the radius bigger.
b. more protons in the nucleus pull the electrons in, making the atomic radius smaller.
c. more electrons pair in orbitals, making the atomic radius smaller.
d. the increased atomic mass makes the atomic radius bigger.

Explanation:

As you move across a period in the periodic table, the number of protons in the nucleus increases. Protons are positively - charged and attract the negatively - charged electrons. This increased nuclear charge pulls the electrons closer to the nucleus, reducing the atomic radius.

Answer:

B. More protons in the nucleus pull the electrons in, making the atomic radius smaller.