Which group of the periodic table contains elements that exist as diatomic molecules?

Answer 1

There is a firm IUPAC convention about the numbering of the groups in the Periodic Table. There does not appear to be one about numbering the periods. Sometimes the first row, containing only H and He is regarded as period 1, or sometimes as period Zero. I will presume that your question was using the first numbering, and frame an answer with respect to elements Na --> Ar

Most of the lighter elements in the periodic table will form X2 gases. The ones that will not are

(i) Those that have an exactly filled subshell in the electron structure of their atom,

and

(ii) Those that do not have significant vapour pressure below temperatures where molecules cannot exist, and all matter is monatomic.

Na & Cl will form vapours of Na2 and Cl2 respectively.

Al & Si do not evaporate until very high temperatures, but low enough that some diatomic molecules can be found in what are largely monatomic vapours.

P & S form vapours of P4 and S8 respectively at low temperatures around their respective boiling points, but in each of these cases there is a higher temperature range where P2 or S2 molecules can be observed.

Mg and Ar do not form diatomic molecules in the gas (or any other) phase.

Answer 2

Iodine, Bromine, Chlorine, Fluorine, Oxygen, Nitrogen, and Hydrogen are all diatomic elements. You can remember this as I bring clay for our new house because the abbreviations of the elements are I Br Cl F O N H

Answer 3

Group 7 (sometimes called group 17) the halogens all form diatomic molecules. Under normal conditions bromine is liquid although it fumes. Iodine is shiny solid that sublimes , i.e doesn' t liquify when heated.. Not much is known about astatine but it is believed to be similar to iodine.

So on a simple count the halogens win with two diatomic gases under normal conditions.

However other groups have elements that form diatomic molcules eg Group 6 (group 16) has Oxygen, and group 5 (group 15) has nitrogen, group 1 has hydrogen.

All of the gaseous elements are diatomic with the exception of the Noble Gases.

Answer 4

The element in period three that is diatomic is Chlorine (Cl) . This is because it has seven electrons in its outer shell, and another Chlorine atom can fill that easily.

Answer 5

The following elements form diatomic molecules

H, N, O, F,Cl, Br, I

Answer 6

There are five diatomic elements that are gases: hydrogen (H2), nitrogen (N2), oxygen (O2), fluorine (F2), and chlorine (Cl2).

Answer 7

Period Two - Nitrogen, Oxygen and Fluorine.

Answer 8

Chlorine, as a gas it's Cl2, in period 3 exists as diatomic molecules at STP.