Classification of Elements & Periodicity in Properties Test 9

Lithium shows similarity in prperties with that of Mg which is stated by the diagonal relationship in periodic table

Non metallic oxides are acidic.

We know that Fluorine has a charge of -1 which then means 'A' has to have a charge of +3. I got that from the AF₃. If Iodine is substituted for Fluorine, the answer should be B. AI₃ because Iodine also has a charge of -1. Although the actual answer should be 2AI₃ because Iodine is also a diatomic element which would give us the reaction 2A+ 3I₂ >>> 2AI₃.

Carbon has 4 electron in its outermost shell. So it is difficult to loose electrons or gain electrons. That's why carbon forms covalent bond by sharing of electrons.

A basic oxide is one which dissolves in water gives a base. MgO when dissolved in water gives Mg(OH)2 which is a base and others give acids

Among the elements of group 17, fluorine is the most reactive owing to its electronegativity and small size of atom.Also extremely high oxidizing power and low dissociation energy of F-F bond is responsible for its reactivity.

Valence of representative element is usually equal to the number of valence electrons and/or equal to eight minus the number of valence electrons.

A carbon atom has four valence electrons. The number of valence electrons of any atom of an element can be determined by the period table group in which the element is classified. There are a total of 18 groups on the period table group.

The valency of sulphur is 2 and the valency of aluminium is 3 hence by crossing method by which we were making the compounds in 9th standard we get it as Al₂S₃.

Be and Al show diagonal relationship and hence resembles each other closely.

Reducing agents reduce others by oxidizing itself. Elements which lose electron become oxidize and reduce other elements by donating electron.

Reason behind it is that fluorine is more electronegative element than oxygen.

On moving down a group since the number of valence electrons remains the same, all elements exhibit same valence.

In Na₂O oxidation state of Na is +1.
It gains 2 electrons so, the oxidation state is +1 which is equal to one oxygen atom (2 electrons)

Neutral oxide. Neutral oxides are oxides which are neither acidic nor basic. In other words, oxides which neither react with acids or with bases are called neutral oxides. Some examples of neutral oxides are nitrous oxide (N2O), and carbon monoxide (CO).

Sodium oxide is more basic than Magnesium oxide. A binary compound of an element with oxygen, in which Oxygen atom is electronegative is called an oxide. The oxides which react with water and produce alkali and can neutralise acids forming salt and water are called basic oxides. Na₂O, MgO are basic oxides.

Fluorine has highest electronegativity among all known elements, so it shows only negative oxidation states.

Valency is defined as the number of electrons in the outermost shell of an element . As the last shell(third shell) has one electron in it the valency of sodium(Na) is 1 or +1 as it looses that electron to form a cation and achieve noble gas configuration.

Sodium has 11 electrons: its atomic number is 11, so it has 11 protons; atoms are neutral, so this means sodium also has 11 electrons.

First elements of each group in the p-block elements shows anomalous behaviour due to:

• Small size
• High electronegativity
• Non-availability of empty d-orbitals

Due to these reasons, compounds of the first elements of each group are highly covalent and show maximum covalency of four.

The Group II elements are powerful reducing agents. A reducing agent is the compound that gets oxidised in the reaction and, therefore, loses electrons.

M = Mg, Ca, Sr,Ba --> I will be using 'M' as the general symbol for a Group II element in this topic.