# Why are groups 13 through 18 referred to as the P block of the periodic table?

## Why are groups 13 through 18 referred to as the P block of the periodic table?

The p-block is the area of the periodic table containing columns 3A to column 8A (columns 13-18), not including helium. There are 35 p-block elements, all of which have valence electrons in the p orbital. The p-block elements are a very diverse group of elements with a wide range of properties.

### Which sublevels are filled by valence electrons?

The valence electrons for the representative (main) group of elements are found in the outermost (highest energy) s and p sublevels. They are often together called the valence shell.

#### How much greater is the atomic number of the fourth element in group 18 than the preceding element?

Chemistry Test 1

How much greater is the atomic number of the fourth element in groups 1,2, and 18 than the preceding element? 18
Krypton, atomic number 36, is the fourth element in Group 18. What is the atomic number of xenon, the fifth element in Group 18? 54

What do the group numbers tell us about the atoms in groups 1/2 and 13 18?

For groups 1 and 2, the number of valence electrons for elements in those groups is 1 and 2 respectively. For groups 13-18, subtract 10 to get the number of valence electrons for elements in those groups, so group 13 elements have 3 valence electrons, and group 14 elements have 4 valence electrons, and so on.

What does the group number on a valence electron mean?

The group number indicates the number of valence electrons in the outermost shell. Specifically, the number at the onesâ€™ place. However, this is only true for the main group elements.

## How many electrons are in the s sublevel?

maximum. The s sublevel has just one orbital, so can contain 2 electrons max. The p sublevel has 3 orbitals, so can contain 6 electrons max. The d sublevel has 5 orbitals, so can contain 10 electrons max. And the 4 sublevel has 7 orbitals, so can contain 14 electrons max. In the picture below, the orbitals are represented by the boxes.

### How are valence electrons found in transition elements?

Okay, so now that we know how shells are filled, we can move further to find the number of valence electrons in the transition elements. Consider Scandium (Sc) with its atomic number of 21. Filling the electrons according to our rule, we observe that the 21st electron occupies the 3d sub-shell.

#### Where are the electrons in the s block?

Atomic numbers 3 and 4 are in the second row of the s block (look for them in the bottom half of in image below), signifying that the 3rd and 4th electrons are in the 2s sublevel. Atomic numbers 5 through 10 are in the first row of the p block, and the p sublevels start on the second energy level.