Question: What Is Period 3 On The Periodic Table?

Why is chlorine in period 3?

Chlorine.

It has the highest electron affinity and the third highest electronegativity of all the elements; thus chlorine is a strong oxidizing agent..

Is K an alkali metal?

Group 1A (or IA) of the periodic table are the alkali metals: hydrogen (H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).

Why is 3rd shell 8 or 18?

Originally Answered: According to the 2-8-8 rule, the 3rd orbital has only 8 electrons in its valence orbital, but from the formula 2n^2, the 3rd shell would have 18 electrons in its valence orbital.

What property decreases across Period 3?

The graph shows how atomic radius varies across period 3: as the atomic number increases, the atomic radius decreases.

Why does electronegativity increase across Period 3?

Why does electronegativity increase across a period? Consider sodium at the beginning of period 3 and chlorine at the end (ignoring the noble gas, argon). … Electronegativity increases across a period because the number of charges on the nucleus increases. That attracts the bonding pair of electrons more strongly.

Why does Period 4 have 18 elements?

There are seven horizontal rows, or periods, on the periodic table. Because the 3d sublevel does not fill until after the 4s sublevel, the fourth period contains 18 elements, due to the 10 additional electrons that can be accommodated by the 3d orbitals.

What are the first three periods of the periodic table called?

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.

Which two periods are known as short periods?

The first period is the shortest period containing only 2 elements. The second and third periods are short periods. The population of each short period is eight elements.

Does Period 3 have 5 valence electrons?

Phosphorous is the 5th element from the left in the third period so it has five valence electrons.

Why do melting points decrease across Period 3?

Phosphorus, sulfur, chlorine and argon There are are van der Waals’ forces between its atoms. The melting and boiling points of these elements are very low because: van der Waals’ forces are very weak forces of attraction … little energy is needed to overcome them.

Where is Period 3 on the periodic table?

Period 3, or the third period, refers to the third row from the top of the periodic table.

What is group and period in periodic table?

All the different elements are arranged in a chart called the periodic table. Here are the main features of the table: the horizontal rows are called periods. the vertical columns are called groups. elements in the same group are similar to each other.

Is a period 4 halogen?

The term “halogen” means “salt-former” and compounds containing halogens are called “salts”. Due to the halogens high reactivity, they tend to exist in nature as compounds and ions. All halogens have 7 electrons in their outer shells, giving them an oxidation number of -1….Halogens.4 IVB 4B5 VB 5B6 VIB 6B7 VIIB 7B17 VIIA 7A12 more columns

Why is the period?

The ovaries release the female hormones estrogen and progesterone . These hormones cause the lining of the uterus (or womb) to build up. The built-up lining is ready for a fertilized egg to attach to and start developing. If there is no fertilized egg, the lining breaks down and bleeds.

Does boiling point increase across a period?

Melting and boiling points increase across the three metals because of the increasing strength of their metallic bonds. The number of electrons which each atom can contribute to the delocalized “sea of electrons” increases. The atoms also get smaller and have more protons as you go from sodium to magnesium to aluminum.

What is the 3rd element?

Lithium is the element that is atomic number 3 on the periodic table. … Lithium is a soft, silvery, light alkali metal denoted with the symbol Li.

Why does reactivity decrease across Period 3?

Reactivity of Elements (decreases down the group) This is due to the fact that atomic radius increases in size with an increase of electronic energy levels. This lessens the attraction for valence electrons of other atoms, decreasing reactivity.

Why third period has only 8 elements not 18?

The electron capacity of third shell is 18. So the third period should actually contain 18 elements. But it contains only 8 elements due to the law of electron octet. … This is because of the fact that electrons are filled in these shells in the increasing order of electrons.

What do Period 3 elements have in common?

In the whole of period 3, the outer electrons are in 3-level orbitals. These are all the same sort of distances from the nucleus, and are screened by the same electrons in the first and second levels. The major difference is the increasing number of protons in the nucleus as you go from sodium across to argon.

Which alkali metal is in Period 3?

sodiumAn alkali metal in period 3 is sodium.

Why does the 3rd period have 8 elements?

According to the 2n2 rule, the maximum number of electrons in the third period = 2 x (3)2 = 18. But, the last shell cannot accommodate more than 8 electrons so, the number of electrons in third period is 8. Hence, the number of elements is also 8.