# Question: How Would You Justify The Presence Of 18 Elements In 4th Period?

## What is the basis of arrangement of elements in the periodic table?

Elements are arranged on the basis of increasing order of atomic numbers.

The horizontal rows in the periodic table are called Periods and the vertical columns are known as the Groups.

The elements in the Modern Periodic Table are arranged in 7 Periods and 18 Groups..

## Which out of 4s & 4p has more energy?

Energy is directly proportional to (n+l) value. For 4s,4p,3d the (n+l) value is 4+0=4,4+1=5,3+2=5 respectively. Thus 4s has the least energy. Thus in accordance to Aufbau’s rule, given statement is false.

## How many electrons are present in 4th period?

18 electronsThe fourth energy level has 18 electrons. The fourth energy level of the periodic table includes the 4s 3d and 4p orbitals. The 4p orbital holds 6 electrons.

## What are bridge elements?

Bridge elements are elements that belong to period 2 of the periodic table. Bridge elements have acquired the name because of a unique characteristic that the elements showcase in the group. … Bridge elements show a cross or a diagonal relationship with the 3rd-period elements in the periodic table.

## Why there are 18 elements instead of 32 in 4th period?

Account for the fact that the 4th period has eighteen and not eight elements. Therefore, 18 elements (not eight) are present in the 4th period. The 4d and 4f sublevels are higher in enthalpy than 5s and hence are filled up in the next periods.

## How many elements are there in the 4th Period explain with reason?

18The total number of elements present in the 4th period of the modern periodic table is 18. These include two s block elements, 6 p block elements and 10 d block elements.

## Why does the fourth period have 18 and not eight element?

After the filling of 4s orbital, instead of 4p orbitals, there starts the filling 3d orbitals. This is in keeping with the fact that 3d orbitals have less energies than 4p orbitals. Thus 10 elements are built up by the filling of 3d orbitals. … Hence the fourth period consists up of 18 and not 8 elements.

## Why is 3D in the 4th period?

As it has been mentioned, electrons fill orbitals from the lowest energy, to the highest. … As you can see, the 4S orbital is filled BEFORE the 3D orbital as it has a lower energy, and therefore 3D has to be placed in the 4th row in the periodic table, after 4S.

## Why does the first periodic table have two elements?

There are only two elements in the first period: hydrogen and helium. … This is because in quantum physics, this period fills up the 1s orbital. Period 1 elements follows the duet rule, they only need two electrons to complete their valence shell. These elements can only hold two electrons, both in the 1s orbital.

## Why noble gases are called bridge elements?

Answer. Answer: Bridge elements are elements that belongs to period 2 of the periodic table. They are called so because they show resemblance in property diagonally i.e the elements of period 2 show resemblance to the the elements of period 3.

## Why are there only 18 elements in 4th period?

The third period is similar to the second, filling the 3s and 3p sublevels. Notice that the 3 d sublevel does not actually fill until after the 4s sublevel. This results in the fourth period containing 18 elements due to the additional 10 electrons that are contributed by the d sublevel.

## Why Period 2 elements are called bridge elements?

the period 2 element is known as bridge element because they show similarity in properties with elements of next group and subsequent period. for eg beryllium to aluminium.

## Which elements is not part of period number 4?

Answer. Explanation: Palladium is a chemical element with the symbol Pd and atomic number 46, on period 5-6.

## Why is 3rd shell 8 or 18?

In this sense the third shell can hold 8 electrons. … In this sense the third shell can hold a total of 18 electrons. So the third shell can be considered to hold 8 or 18 electrons but in total the third shell can hold 18 electrons.

## Which comes first 3d or 4s?

The aufbau principle explains how electrons fill low energy orbitals (closer to the nucleus) before they fill higher energy ones. … This means that the 4s orbital which will fill first, followed by all the 3d orbitals and then the 4p orbitals.

## What is a normal element?

✨Any element found in the s and p blocks in the periodic table are known as normal elements. ✔These elements have incomplete outermost shell. … ✔✔Elements belonging to the s- and p-blocks in the periodic table are called the normal elements or main group elements.

## How many elements are in 4th period in D Block?

The fourth period contains 18 elements beginning with potassium and ending with krypton – one element for each of the eighteen groups. It sees the first appearance of d-block (which includes transition metals) in the table.

## How would you justify the presence of 32 elements in 6th period?

In the sixth period (n = 6) of the periodic table, 6s, 4f, 5d and 6p orbitals are filled in the increasing order of the energy. Total 16 orbitals are available each of which contains a maximum 2 electrons. Thus, the sixth period can accommodate maximum 32 elements.