What do alkali metals and noble gases have in common?

They are all in fact very soft metals that can be cut with a knife and have relatively low melting temperatures. They do not occur naturally because they react readily with air and moisture and so need to be stored under oil.

Where are the alkali metals and noble gases on the periodic table?

Groups are numbered 1–18 from left to right. The elements in group 1 are known as the alkali metals; those in group 2 are the alkaline earth metals; those in 15 are the pnictogens; those in 16 are the chalcogens; those in 17 are the halogens; and those in 18 are the noble gases.

Why are the alkali metals in period 1 so reactive?

Alkali metals are among the most reactive metals. This is due in part to their larger atomic radii and low ionization energies. They tend to donate their electrons in reactions and have an oxidation state of +1.

What characteristics do all of the elements in a period have in common?

A period in the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor.

Why do alkali metals react with noble gases?

So they outer electron gets further from the nucleus. The attraction between the positive nucleus and negative electron is less. This makes it easier to remove the electron and makes the atom more reactive. The alkali metals have low melting and boiling points compared to most other metals.

Why are alkali metals so reactive and noble gases not?

They are silvery or gray in color. They are also relatively soft and low in density. Alkaline Earth metals are very reactive because they readily give up their two valence electrons to achieve a full outer energy level, which is the most stable arrangement of electrons.

What does each period represent in the periodic table?

The horizontal rows of the periodic table are called periods. Each period corresponds to the successive occupation of the orbitals in a valence shell of the atom, with the long periods corresponding to the occupation of the orbitals of a d subshell.

What happens when an alkali metal reacts with a noble gas?

In each reaction, hydrogen gas is given off and the metal hydroxide is produced. The speed and violence of the reaction increases as you go down the group. The hydroxides formed in all of these reactions dissolve in water to form alkaline solutions.

Why alkali and alkaline earth metals are reactive?

Alkaline Earth metals are very reactive because they readily give up their two valence electrons to achieve a full outer energy level, which is the most stable arrangement of electrons. Reactivity increases from the top to the bottom of the group.

Why were the noble gases once called inert?

The noble gases were previously known as ‘inert gases’ because of their perceived lack of participation in any chemical reactions. The reason for this is that their outermost electron shells (valence shells) are completely filled, so that they have little tendency to gain or lose electrons.

Why does each period have a different number of elements?

All of the elements in a period have the same number of atomic orbitals. For example, every element in the top row (the first period) has one orbital for its electrons. All of the elements in the second row (the second period) have two orbitals for their electrons. As you move down the table, every row adds an orbital.