what does the group number of a column in the periodic table represent?

Question

also what does the period number of a row represent?

Answer 1

The group number tells you the number of valence electrons that the elements on that family has.

Alkali metals, Group 1, 1 valence electron
Alkaline earth elements, Group 2, 2 valence electrons
Group 13 - use only last digit, 3 valence electrons
Group 14 - 4, Group 15 - 5, Group 16 - 6, Group 17 - 7, Group 18 - 8

For the transitions elements is a little bit more difficult, the group number tells you the total number of electrons in d and s subshells.

Group 3 Sc and so on - nd1n+1s2
Group 4 Ti and so on - nd2n+1s2
etc, etc. etc.

There are exemptions;

Cr is [Ar]3d54s1, even though is in group 6.
Cu is [Ar]3d104s1, not [Ar]3d94s2 as expected. Still adding the number of d electrons to the number of s electrons does give you the group number.

As the number of d electrons increases, they become less important in determining valence electrons. If the number is low, they can be counted, if it is high, some will count, others will not.

Example, Ti [Ar]3d24s2, Ti^2+ [Ar]3d2, Ti^4+ [Ar]

Cu [Ar]3d104s1 Cu+ [Ar]3d10, Cu2+ [Ar]3d9

The period number tells you which shell will fill first, after core electrons.

Li, period 2 [Ne]2s1, Be [Ne]2s1, B [Ne]2s22p1 and so on.

K, period 4 [Ar]4s1, Ca[Ar]4s2, Sc [Ar]3d14s2, in the transition metals you will n - 1 from the period number. After the d orbitals are filled, you continue with the 4p orbitals, so Ga, right after Zn, [Ar]3d104s14p1, Ge, [Ar]3d104s14p2, and so on, until you reach Kr, which will close the 4 subshell, so Rb will be [Kr]5s1 and you continue as before, but now on period number 5. So for the transition metals on that period, Y through Cd, the electrons enter the 4d10 subshell before they enter the 5p subshell.

Answer 2

Periodic Table Group Numbers

Answer 3

The Group number in the Periodic Table indicates the number of electrons in the outer energy shell, up to a maximum of 8 electrons.
Group 1 the Alkali metals - 1 electron
Group 2 the Alkali Earth Metals - 2 electrons
Group 7 the Halogens - 7 electrons
Group 8(0) the Inert Gases - 8 electrons.

The Period in the Periodic Table represents the number of Inner Energy shells that have a complete electron complement.
Period 1 - only one energy shell
Period 2 - one complete inner energy shell
Period 3 - two complete inner energy shells
& so on.
The Periodic Table is a very 'Angular' presentation of elements. A 'web - site' called 'Chemical Galaxy' gives a beautiful coloured diagram of the elements - its worth a look and a copy. This diagram is repeated in Wikipedia.

Answer 4

What I have known so far about the arrangement of elements in the periodic table is the elements in the periodic table are arranged in an increasing order of proton number , ranging from 1 to 113. Each vertical columns are known as Group 1 to Group 18. Each horizontal rows is called period. The horizontal rows are known as Period 1 - Period 7 .The period of an element is equal to the number of shells occupied with electrons in the electron of the element. For example : Sodium and magnesium form basic metal oxides whereas alumiun forms amphoteric oxide . On the other hand , silicon , phosphorus , sulphur and chlorine form acidic non-metal oxides. Refer to the Periodic Table and you'll see the differences of the atom arrangement. I suggest that you do a lot of exercise on it and try to ask your teacher for further details .

Answer 5

Group number is the number of valence electrons in its outer shell. Period number represents principle energy level.

Answer 6

Really, the group number of a column does not mean anything. They are a means of keeping track of properties and of elements that may be related (distantly) to one another. By this I mean groups IA, IIA, and IIIA, and IB, IIB, and IIIB. This is especially true after the renumbering of the columns, which correspond to nothing at all. Also, the period number has no special meaning.

The periodic table is a valuable guide to learning chemistry. There are no iron laws of chemistry there.

Answer 7

The group number tells you how many outside electrons and what charge the atom will have as an ion.
The period number tells you the number of rings of electrons.

Answer 8

thanks for asking the question I was about to do the same thing