Whole family.
The elements on the periodic table are arranged in periods and groups. The periods run across the table horizontally from left to right, whilst the groups run vertically from top to bottom. Elements from the same group tend to have similar chemical properties since they have the same number of electrons in their outer shells. :) You can find which elements are in which groups and more about the groups themselves by looking at a periodic table for the numbers above the columns or searching Google for "group 1" for example.
Valency
Because it helps with their electron configuration.
You can determine how many valence electrons an atom has by what family the element of the atom is in. For instance, if the element is in family 8A, the number of valence electrons will be 8. Or, if the element is in family 2A, the number of valence electrons for the atom will be 2. So, whatever number family the atom is in, the number of valence electrons equals that.
This is a chemical element. You can find the how many electron in a single atom by using a periodic table.
Every elements have the electrons of an atom distribution or a molecule in molecular orbitals and it is called electron configuration. The element that can be grouped in the family with above electron configuration is called antimony.
The elements on the periodic table are arranged in periods and groups. The periods run across the table horizontally from left to right, whilst the groups run vertically from top to bottom. Elements from the same group tend to have similar chemical properties since they have the same number of electrons in their outer shells. :) You can find which elements are in which groups and more about the groups themselves by looking at a periodic table for the numbers above the columns or searching Google for "group 1" for example.
An element can either gain or lose electrons to achieve a noble gas electron configuration. Such an electron configuration gives an atom of an element a full outer shell, thereby making that element's ion nonreactive. Metals tend to lose electrons, and become cations, whereas nonmetals tend to gain electrons, and become anions. The amount of electrons an element gains of loses is based on the group/family the element is found in on the Periodic Table.
Valency
The period (row) indicates how many electron shells the element has and the family (column) indicates how many valence electrons the element has.
Elements in group 17 need one electron to gain a stable electron configuration. Two atoms of the same element or two elements in this family forms compounds with a single covalent bond. Examples are chlorine, bromine or iodine chloride.
The valance electron configuration is the same in each at ns1 where n = the period number.
The reason for similar properties among the elements is due to the resemblance in the electronic configuration of all the elements of a family. For example :- Each element of Alkali metals family has 1 electron in their outermost shell. Hence, they all have similar properties
Because it helps with their electron configuration.
Polonium has the lowest electron affinity in the oxygen family.
The element family that iron belongs to on the periodic table is the transition metals family. Other elements in this family include cobalt and nickel.
The elements with a s2 p3 electron configuration are located in the 5A (or 15) column of the periodic table: nitrogen, N; phosphorus, P; arsenic, As; antimony, Sb, and bismuth, Bi.