the number of electrons in the outermost shell of an element is represented in the periodic table as the group number that element is situated in. the number of electrons in all shells of an element is represented in the periodic table as the element’s atomic number.

1 Answer. The group number of the representative elements = the number of valence electrons.

The number of valence electrons in elements of the p-block is equal to the group number minus 10. As an example, sulfur is located in Group 16, so it has 16 – 10 = 6 valence electrons. Since sulfur is located in period 3, its outer electron configuration is 3s23p4.

Across each row, or period, of the periodic table, the number of valence electrons in groups 1–2 and 13–18 increases by one from one element to the next. Within each column, or group, of the table, all the elements have the same number of valence electrons.

All Group 1 atoms can lose one electron to form positively charged ions. For example, potassium atoms do this to form ions with the same electron configuration as the noble gas argon. Group 2 atoms lose two electrons to form positively charged ions. Most elements in Group 3 lose three electrons to form 3+ ions.

chlorine

According to the periodic table above, phosphorus belongs to Group 5A. Therefore, Its valence electrons should be 5. The outermost orbitals, 3s2 3p3 , contains 5 electrons. Thus, valence electrons for P is 5.

INTRODUCTION: Phosphorus can form bonds with many other elements. Also it can form bonds with varying number of atoms (Coordination Number), which can vary from 1 to 6.

Phosphorous shows both the valencies 3 and 5. Phosphorous with valency 3: With three unpaired electrons in three p orbitals, phosphorous shows valency 3, like in case of compound PCl3. Thus, phosphorous atom undergoes sp3d hybridisation to form five equivalent sp3d orbitals each containing one unpaired electron.

The valency of an atom is equal to the number of electrons in the outer shell if that number is four or less. Otherwise, the valency is equal to eight minus the number of electrons in the outer shell. Once you know the number of electrons, you can easily calculate the valency.

sodium donates its outermost electron and chlorine atom gains the same electron to complete its octet. Na+ and Cl− ions combine to form an ionic compound. Complete Solution : The valency of an element is a combining capacity of an atom .

The key difference between electrovalency and covalency is that the electrovalency is the number of electrons that an atom either gains or losses in forming an ion whereas covalency is the number of electrons that an atom can share with another atom.