Passage IV

Figure 1 is a simplified periodic table giving the name, symbol, and atomic number (number of protons in the nucleus) for 20 elements. The elements in a column belong to a group. The elements in a row belong to a period.

Table 1 gives the melting point at 1 atmosphere (atm) of pressure (the MP), the boiling point at 1 atm (the BP), and the atomic radius for one or more of the elements in each group. The atomic radius, in picometers (pm; 1 pm = 10-12 m), is a measure of the size of an atom. Table 1 also lists an ion for each element and the ionic radius of that ion (a measure of its size).

21. Barium (Ba), like Sr, is a Group 2A element. The atomic number of Ba is 56. Based on Figure 1 and Table 1, which of the following is the most plausible set of values for the atomic radius of Sr and of Ba ?

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

It can be seen from table 1 that the greater the atomic number of an element in a specific Group, the greater the atomic radius;

So it can be predicted that the atomic radius of Sr is greater than that of Group 2A Ca's 197, and Ba's atomic radius should be larger, so option C is in line