Any type of energy or an abstract thing is non-matter. Examples are- Sunlight, Gravity, Heat, Reflection, etc.

$Na$ represents the symbol of sodium.

Classification of things means a grouping of things with similar properties together.

The metals which exists as liquids above 30 degree celcius are :-

1)Mercury-(Also in room temperature) 

2)Cesium

3)gallium

Carbon dioxide is a naturally occurring chemical compound composed of 2 oxygen atoms each covalently double bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state, as a trace gas at a concentration of $0.04 \%$ by volume.

A chemical element is a pure chemical substance consisting of a single type of atom distinguished by its atomic number, which is the number of protons in its atomic nucleus. If you change the number of protons an atom has, you change the type of element it is.

Classification of matter helps us to:

Iron(II) sulfide or ferrous sulfide is a chemical compound with the formula $FeS$. Iron sulfides are often non-stoichiometric. powdered iron sulfide is pyrophoric (ignites spontaneously in air).

Things are always classified to make 

K belongs to first group. It is a normal metal. Elements of d block are transition metals. Hence K is not a transition metal

Lead $(Pb)$ is not a compound. It is an element present in its pure form so it a single homogeneous identity. Compounds have two or more elements present in the uniform composition in the compound state.

Element is a chemical substance which is composed of same type of atoms or only of single kind e.g., periodic table consist of all elements in its pure form like $Na,\ Mg,\ Cu,\ Pb$ etc.

Elements are made up of only one type of atoms which cannot be further broken down.

Compounds are made up of elements combined in a fixed ratio by mass.

Iron, gold and platinum are all metallic elements. They are made up of atoms. Camphor on the other hand is a compound made up of elements like C, H and O.

In the above examples, water is a compound and air is mixture. Water consists of oxygen and hydrogen chemically combined whereas air is a mixture which consists of oxygen, nitrogen and other gases which are only physically combined.

Water exist in all the three states solid as ice, liquid as water and gas as water vapours.

A pure substance which is made up of only one kind of atom and cannot be broken into two or more simpler substances by physical or chemical means is referred to as an element. An element is homogeneous in nature; it is a pure substance, made up of only one kind of atoms. For example, iron and silver are made of only iron and silver atoms.

Compounds is a pure substance made up of two or more elements combined chemically in a definite (or constant) proportion by mass.

Elements are pure substances which are made up of only one kind of atom. All atoms in an element are identical but atoms of different elements are different.

Compound is made up of two or more elements. Ozone is made up of 3 oxygen atoms which are identical. Hence, its an element and not a compound.

Hydrogen peroxide is formed when two atoms of hydrogen form a bond with two atoms of oxygen that have bonded to each other. Octane is a hydrocarbon consisting of hydrogen and carbon. Sodium bicarbonate (baking soda) can be produced from the reaction of carbon dioxide with an aqueous solution of sodium hydroxide, which creates sodium carbonate; it is then combined with carbon dioxide molecules to produce sodium bicarbonate. All the compounds are made up of different elements and have properties different from their constituent element.

All the above examples are mixtures and not compounds. Mixtures are impure substance made up of two or more pure substances. They are not chemically mixed and can be separated by physical means.

Antimony and Arsenic belong to the category of metalloids. A $metalloid$ is any chemical element which has properties in between those of metals and nonmetals, or that has a mixture of them.

In the given classification, the Tiger is not suitable as it is animal and all the others are plants.

Hydrogen peroxide $= H _2O _2$

Rose is not correctly classified as it is a plant, not mammal. Mammals are the types of animal.

Baking soda (sodium hydrogen carbonate $ \displaystyle (NaHCO _3)$ or sodium bicarbonate ) is a compound. It is formed by chemical combination of elements $Na, \ H, \ C, \ O $.

In the fourth period of periodic table there is filling of 4s,3d,4p orbitals. So the total number of orbitals to be filled $=1(4s)+5(3d)+3(4P)=9$

Atoms and molecules are all composed of matter. Matter is anything that has mass and takes up space.
Three basic forms of matter are solid, liquid and gas.

Milk is not compound. A compound is an entity consisting of two or more different atoms associating with chemical bonds. Milk is an emulsion or colloid of fat globules within a water-based fluid that contains dissolved carbohydrates and protein aggregates with minerals.

If you heat iron filings ans sulphur to a sufficiently high temperature you form iron sulphide 
$Fe + S \rightarrow FeS$
If you add HCl to this the following reaction occurs: 
$FeS + 2HCl \rightarrow FeCl _2 + H _2S$ 
$H _2S$ gas is given off and iron chloride is produced. 

A compound is a chemical species that is formed when two or more atoms join together chemically, with covalent or ionic bonds.
Examples: $NaCl$, $KCl$ and $NaOH$

Brass is not an element but it is an alloy made of copper and zinc the proportions of zinc and copper can be varied to create a range of brasses with varying properties.

A mixture is made when you combine matter in a way where the components can be separated again. A compound results from a chemical reaction between components, forming a new substance. For example, you can combine iron filings with sulfur to form a mixture. All it takes is a magnet to separate the iron from the sulfur. On the other hand, if you heat the iron and sulfur, you form iron sulfide, which is a compound.
$Fe+S \rightarrow FeS$

Antonie L. Lavoisier defined element as basic form of matter that cannot be broken down into simpler substances by chemical reactions

Diamond is the purest form of elemental carbon so it is not a compound.

Among these only carbon dioxide is a compound.

The names and symbols of the element is as follows:

The product is water. It is formed after a chemical change (burning) and the properties of water is different from hydrogen and oxygen.

Water is a compound having hydrogen and oxygen atoms in the ratio of 2:1 and properties of water as chemical compound is different from the hydrogen and oxygen elements.

Given that the electronic configuration of X = 2,8,3 and Y = 2,8,6. Thus the valencies they posses to attain noble gas configuration are; X = +3 and Y = -2. Therefore the formula of the compound formed can be written as; $M _{2}X _{3}$.

Element can not be broken down chemically. Elements are made of atoms of only one kind and that cannot be separated by ordinary chemical means into simpler substances.

Water is a chemical compound made up of hydrogen and oxygen combined in the ratio $2:1$ by volume or $1:8$ by mass (2 g of hydrogen combines with 16 g of oxygen).

The lightest and the most abundant element in the universe is hydrogen. The percentage of hydrogen in the universe is more than $91$%.

An element consists of only one type atom. All compounds, mixtures etc. consists of element. Hence, element is the basis of all the matter.

Phosphorus is used in making smoke bombs.

Iron is an element found in nature as the third most abundant element in the earth's crust.

Snow and ice cannot form compounds because they are same water molecules in solid state grouped together by hydrogen bonds. Snow and ice cannot form compound because they both are similar.

Baking soda is a compound because it's composed of molecules that are all identical. It has the chemical formula $NaHCO _3$ and the chemical name sodium hydrogen carbonate. Pure baking soda is a compound, NaHCO3. But in most cases the white powder will be a mixture between $NaHCO _3$ and $Na _2CO _3$, which resulted after the decomposition of $NaHCO _3$:

$2NaHCO _3 \rightarrow  Na _2CO _3 + CO _2 + H _2O$

Oxygen and hydrogen are two elements and when they react they must generate another compound. Their product is not a mixture and  their result is a different compound with different properties.

Matter is any substance that has mass and takes up space; this includes atoms and anything made up of these, hence it can be hard or soft.

Longest period is 6th period. It contains 32 elements. It starts with Caesium. The last element is Radon. 

Three elements A,B and C. B is a noble gas, A has atomic number 1 less than B and C has 1 more than B. Hence number of valence shell is same in A and B because on adding one electron to Noble gas that is 18 group next electron will occupy, alkali metals group in a next period hence increases in shell number.

Heating of any substance will give the same compound unless temperature is taken upto such high where the compound breaks down into its constituents. Dissolving common salt in water will give brine solution.

(P) Liquid have a definite volume as the particles are in contact with each other.

Atomic mass is defined as a multiple of one-twelfth the mass of the carbon-12 atom.

Salt like $NaCl, MgCO _3, KCl,$ etc are compounds. Iron is an element. $O _2$ is a molecule. Diamond is pure elemental carbon compressed to its crystal form.

(A)-(iii, q); (B)-(i, r); (C)-(iv, p); (D)-(ii, s)

Quantum number $n = 4,:l = 0$ corresponds to 4s electrons. When two 4s electrons are lost, a dipositive ion is formed. The configuration of the element could be $3s^23p^64s^2 :or :3s^23p^63d^{1-10} 4s^2$. Since the atom of the same element can lose one more electron, it should be the 'd' block element. 

According to Aufbau principle the order of filling of orbitals is:
$1s\ 2s\ 2p\ 3s\ 3p\ 4s\ 3d\ 4p\ 5s\ 4d\ 5p\ 6s\ 4f\ 5d\ 6p$
For maximum shell of 5, electrons will be filled upto 5p orbital as (each period)
$(1s^2)(2s^22p^6)(3s^23p^6)(4s^23d^{ 10 }4p^6)(5s^24d^{ 10 }5p^6)$
$2+8+8+18+18=54$
Therefore maximum number of atoms would be 54.
option B is correct.