Match the following. 1. an ancient study or art which attempted to combine science and philosophy to solve worldly problems metal 2. a homogeneous mixture of elements with metals to form metallic solids atom 3. the simplest unit of an element that still retains the properties of that element compound 4. two or more elements joined together such that the elements have lost their individual identity alloy 5. a primary substance that cannot be divided into separate substances element 6. the group of elements that are good conductors of electricity and heat alchemy 7. the group of elements that are poor conductors of electricity and heat nonmetal

1. an ancient study or art which attempted to combine science and philosophy to solve worldly problems : Alchemy

Explanation : Alchemy is a branch chemistry which was popular during ancient times. It basically dealt with transformation of metals into gold. Alchemists combined certain known principles of chemistry with philosophical knowledge to find a cure for disease and to prolong life.

2. A homogeneous mixture of elements with metals to form metallic solids : Alloy

Explanation : Mixtures are of 2 types

a) Homogeneous mixture : A homogeneous mixture is the one which has uniform composition. For example when salt is dissolved in water, it forms a solution where we cannot see salt and water separately. But they mix with each other forming a uniform phase.

b) Heterogeneous mixture : In this type of mixture, 2 or more different phases can be seen. For example mixture of oil and water. When we mix oil with water, we can see 2 distinct layers.

Alloy is an example of solid homogeneous mixture. When elements are mixed with metals, they form a mixture which has uniform composition which is known as alloy.

example : Brass - This alloy contains a mixture of copper and zinc.

3. The simplest unit of an element that still retains the properties of that element : Atom

Explanation : An element is an example of a pure substance. An element is made of only one type of representative particle which is an atom.

For example, Sodium is an element and it is made of Na atoms.

4. Two or more elements joined together such that the elements have lost their individual identity : Compound

Explanation : A compound is made of 2 or more elements which has a completely different set of properties than the elements from which it is formed. For example water, H₂O

Water is made of 2 elements, hydrogen and oxygen. Hydrogen is flammable whereas oxygen is required for burning. Yet water is used to extinguish fire. We can see here that elements H and O have completely lost their properties when they form water.

5. A primary substance that cannot be divided into separate substances : Element

Explanation : Element is an example of a pure substance. A pure substance is made of only one type of representative particle and cannot be divided further.

For example Copper is an element. It contains copper atoms. We cannot divide it further into separate substances.

6. The group of elements that are good conductors of electricity and heat : Metal

Explanation : Metals are good conductors of heat and electricity. This is possible because in case of metals, the valence electrons are loosely held. They are capable of escaping the atom and move around freely throughout its structure. These free electrons are responsible for conduction of heat and electricity.

7. The group of elements that are poor conductors of electricity and heat : Nonmetal

Explanation : The atomic structure of non metals is such that their outermost electrons are strongly held. These electrons are not capable of escaping the atom. As a result, non metals do not have free electrons. Therefore they do not carry heat or electricity.

Answer: -

1. An ancient study or art which attempted to combine science and philosophy to solve worldly problems Alchemy

2. A homogeneous mixture of elements with metals to form metallic solids Alloy.

3. The simplest unit of an element that still retains the properties of that element compound Atom

4. Two or more elements joined together such that the elements have lost their individual identity Compound

5. A primary substance that cannot be divided into separate substances element Element.

6. The group of elements that are good conductors of electricity and heat Metals

7. The group of elements that are poor conductors of electricity and heat Non metal