Question

in which of the following options are ca o, s, and ge arranged in order of increasing atomic radius (smallest to largest)?
a. ca, o, s, ge
b. ge, o, s, ca
c. o, s, ca, ge
d. o, s, ge, ca
e. ca, ge, s, o

Explanation:

Step1: Analyze the trend of atomic radius in the periodic table

In the periodic table, atomic radius decreases from left to right across a period and increases from top to bottom down a group.

Step2: Locate the elements in the periodic table

• \(O\) (oxygen) is in period \(2\), group \(16\).
• \(S\) (sulfur) is in period \(3\), group \(16\). Since \(S\) is below \(O\) in the same group, \(r(O)<r(S)\) (atomic radius of \(O\) is less than that of \(S\)).
• \(Ge\) (germanium) is in period \(4\), group \(14\). \(Ca\) (calcium) is in period \(4\), group \(2\). Since in the same period, atomic radius decreases from left to right, \(r(Ge)<r(Ca)\) (atomic radius of \(Ge\) is less than that of \(Ca\)). Also, elements in lower periods generally have larger atomic radii than those in higher periods. So \(r(S)<r(Ge)\) (because \(S\) is in period \(3\) and \(Ge\) is in period \(4\)).

Combining these, the order of increasing atomic radius is \(O < S

Answer:

D. \(O, S, Ge, Ca\)