Question

what is the atomic number of the element located in group 16, period 2 of the periodic table? enter the atomic number. view available hint(s) submit part b if a new element were discovered and it was found to form 1– ions, in which group would you place it in the periodic table? enter the group number. view available hint(s)

Explanation:

Part A

Step1: Recall periodic table structure

In the periodic table, period 2 elements have electron shells \( n = 2 \). Group 16 elements have 6 valence electrons.

Step2: Determine the element

For period 2, the electron configuration starts with \( 1s^2 \). For group 16, valence electrons are 6, so the electron configuration is \( 1s^2 2s^2 2p^4 \). The element is oxygen (O), and its atomic number is the number of protons (equal to total electrons in neutral atom), which is \( 2 + 2 + 4 = 8 \).

Step1: Recall ion formation and group trends

Elements that form \( 1^- \) ions gain 1 electron to achieve a stable octet. This is characteristic of group 17 (halogens), which have 7 valence electrons and gain 1 electron to form \( X^- \) ions.

Step2: Identify the group

Since the element forms \( 1^- \) ions, it should be placed in group 17.

Answer:

8

Part B