 # Why The Number Of Elements In First Period Is Only Two?

## How many elements are there in first period?

First there is the hydrogen period, consisting of the two elements hydrogen, 1, and helium, 2.

Then there are two periods of eight elements each: the first short period, from lithium, 3, to neon, 10; and the second short period, from sodium, 11, to argon, 18..

## What element is in Group 2 Period 3?

magnesiumHence the name of the element is magnesium.

## What element in Period 2 has the most mass?

1 Answer. The element in Period 2 with most mass is clearly the element with the highest atomic number, Z , and that is Ne , Z=10 , 21.08⋅g⋅mol−1 .

## What is the period number?

If you are given with the atomic number of an element you can find it’s period number and group number. The period number is related to the number of electron occupied shells in the element and the period number is linked to its valence electrons.

## What element in Period 2 has the least mass?

LithiumExplanation: Lithium has the least mass, while Neon has the most mass. Lithium: The elements in Period 2 of the periodic table are: Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, and Neon.

## Which is shortest period?

first periodThe first period of the periodic table is the shortest period of the periodic table. The sixth period of the periodic table is the longest period of the periodic table.

## What element is in group 17 Period 2?

Meet the Halogens Halogens are highly reactive nonmetallic elements in group 17 of the periodic table. As you can see in the periodic table below, the halogens include the elements fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).

## How many elements are there in 1st and 2nd period?

Period 1 has only two elements (hydrogen and helium), while periods 2 and 3 have 8 elements. Periods 4 and 5 have 18 elements.

## What’s unusual about Period 1 of the periodic table?

The first period contains fewer elements than any other row in the table, with only two: hydrogen and helium. … Period 1 elements obey the duet rule in that they need two electrons to complete their valence shell. Hydrogen and helium are the oldest and the most abundant elements in the universe.

## What number increases from 3/10 to Period 2?

In the periodic table, atomic number increases from 3 to 10 in period 2. Explanation: Atomic numnber is the total number of protons present in an atom. And, when we move across a period then there occurs an increase in atomic number of the elements.

## How many elements are there in second period?

Period 2 elements obey the octet rule in that they need eight electrons to complete their valence shell, where at most eight electrons can be accommodated: two in the 2s orbital and six in the 2p subshell….Periodic trends.Chemical element8OOxygenChemical seriesReactive nonmetalElectron configuration[He] 2s2 2p47 more columns