Metals and Non-Metals - Class VIII

Hydrogen, oxygen, nitrogen etc. are non-metal and boron, silicon, germanium etc. are metalloids. On the basis of chemical and physical properties, elements are further classified into metals, non metals and metalloids.

Iodine is a non-metal. Even though iodine is a non-metal, it has metallic lustre. It is neither ductile nor malleable. It is a poor conductor of electricity. These are properties of non-metals.

Boron is neither metal nor non metal it is a metalloid.

Heat conduction is the property of metals. In metals, valance electron is free to flow among the atoms. Because of that metals are such good conductors of electricity. These electrons can also carry energy in the form of heat and thus the metals are conductors of heat.

Allotropes are defined as chemical elements which exist in two or more different forms, in the same physical state.

In general, elements located in the left two-thirds of the periodic table are metals, and the non-metals are on the right side of the table. 

True.

Potato chip bags are not full of air, but of nitrogen gas. This is done to prevent the chips from oxidizing, which is part of what makes them go stale. Oxygen is very reactive, and likes to combine with other molecules whenever it can, causing chemical changes to take place.

A purple coloured non-metal which forms a brown solution in alcohol, which is applied on wounds as an antiseptic is iodine. It is also known as tincture iodine. It is basically a weak solution of iodine with only 2 to 7 % iodine dissolved in asolution of water and ethanol along with potassium or sodium iodide.

Wooden scale, glass test tube, paper basket are all non-metals and a poor conductor of electricity and Rubber gloves are similar to these. Also if she is doing any lab work as Wooden scale, glass test tube, paper basket are usually composed of carrying out some experiment then she would need a rubber glove.

Hydrogen is more plentiful than any other element making up about 3/4th the mass of the universe. Helium is second making up almost all of the remaining $25%$. Oxygen is third most abundant element of universe. On earth, oxygen is the most common element making up about $47%$ of earth's mass.

The element $X$ is calcium with atomic number 20 and electronic configuration (2,8,8,2). It has 2 valence electron.

Metal are defined as those element which posses luster, are malleable and ductile and good conductor of electricity. They are hard and have high density.

In the periodic table there are 22 non metals out of which 10 non metals are solids, one non metal is liquid and remaining 11 non metal are gases.
Nitrogen is one of the 22 non metals.

Metalloid is a chemical element with properties in between or that are a mixture of those of metal and non metal. Boron is also one of the metalloids

Metalloids are elements which have some metals property and some non-metals property. The element $X$ is germanium which is metalloid.

Non-metal is an element that usually has low density, a dull appearance, a low melting point, and a poor conductor of heat and electricity.

The most abundant elements in the earth crust is Oxygen as many compounds are in form of their oxides.

Answer : $2, 1$

Graphite is a non-metal. Generally, non-metals are bad conductors of electricity but graphite is an exception. Because the structure of graphite is in such a way that electrons can move freely and conduct electricity. Due to this property, it is used in making of pencil cells. 

Bromine is a halogen and a non metal. It is a red brown liquid at room temperature. Its atomic number is 35. It belongs to fourth period and $VII :A$ group of the periodic table. 

Metals have 1-3 electrons in their outermost orbit. They are present on the extreme left of the periodic table. They tend to donate electrons and obtain the stable electronic configuration of the nearest noble gas. The valency on metals also ranges from 1-3.

The most abundant element in earth's crust is oxygen with$\text{ Percent by weight = 46.1% followed by aluminium with 8.23% by weight.}$
Hence, the answer is option $B$.

Ans : (D) Sand and Shirt

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The
density of non metals isl ow when compared with  metals as metals are
solids and non metals are liquids and gases(Generally solids are more
denser than liquids and gases).
Hence option C is correct.

The
density of  metals are high when compared with  non metals as metals
are solids and non metals are liquids and gases(Generally solids are
more denser than liquids and gases).
Hence option A is correct.

                            	<span class="ng-binding">Non-metals are generally solids and gases. They do not exist as liquids except Bromine. Bromine is a liquid non-metal.</span><div><span class="ng-binding"><br>Hence option D&nbsp; is correct.<br></span></div>

                            	<span class="ng-binding">Generally Non metals are not lustrous(not shiny). But Iodine is the only non metal which is lustrous. Iodine is shiny. Hence, option A is correct.<br></span>

                            	<span class="ng-binding">Metal oxides are basic in nature whereas non-metal oxides are acidic in nature.</span><div><span class="ng-binding"><br></span></div><div><span class="ng-binding">Non-metal oxides are called acidic oxides because when a non-metal reacts with oxygen, it gives an oxide which on dissolution with water gives an acid.<br></span></div><div><span class="ng-binding"><br></span></div><div><span class="ng-binding">&nbsp;Hence, option A is correct.<br></span></div>

                            	<span class="ng-binding">Non-metals are not sonorous as they do not produce sound when they are beaten.&nbsp;</span><div><span class="ng-binding"><br></span></div><div><span class="ng-binding">&nbsp;Hence, option A is correct.<br></span></div>

                            	<span class="ng-binding">Metal oxides forms bases and non metal oxides forms acids when they react with water.&nbsp;</span><span>Metal oxides when they reacted with water it produces bases.&nbsp;</span><span>Hence, option A is correct.</span>

Non
metals are generally not malleable as they can not be beaten into thin
sheets. Substance which can be beaten into thin sheets are called
malleable. Hence, option A is correct.

Non metals are generally solids and gases.They do not exist  as liquids except Bromine.Bromine is liquid.
Hence option B is correct.