Definition Of Elements
An element is the simplest form of matter that cannot be further divided into simpler substances by chemical reactions
More About Elements
- Elements are the building blocks for all matter
- Atom is the general term. Everything is made of atoms
- The term element is used to describe atoms with specific characteristics
- There are about 120 different elements
- You are made up of billions and billions of atoms but you probably won't find more than 40 elements (types of atoms) in your body
- Elements are of three types, metals, non metals and metalloids
- 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
- Familiar examples of elements are carbon, nitrogen, oxygen (non-metals), silicon, arsenic (metalloids), aluminium, iron, copper, gold, mercury, and lead (metals)
- The properties of metals are
- Metals show luster
- Metals are malleable and ductile
- Metals are sonorous
- Metals conduct heat and electricity
- Metals are golden yellow or grey in colour
- The properties of non metals are
- Non metals display a variety of colours
- Non metals are poor conductors of heat and electricity
- Non metals are not lustrous, sonorous or malleable
- Few more examples of non metals are iodine, hydrogen, bromine and chlorine
- The elements having intermediate properties between metals and non metals are metalloids. Ex. Boron, aluminium
- Number of elements occurring naturally are 100
- 92 of them are natural and rest are man made
- Most of the elements are solids
- Eleven elements are in gaseous state at room temperature
- Two elements are liquids at room temperature. They are bromine and mercury
- Elements gallium and cesium become liquids at a temperature slightly above room temperature
- Most elements are generally stable, a small amount of natural transformation of one element to another also occurs in the decay of radioactive elements as well as other natural nuclear processes
Questions:
Questions. A substance that cannot be broken down into a simpler form by ordinary chemical means is called a(n)
A. Element
B. Compound
C. Mixture
D. Isotope
Answer: A
Questions. The smallest unit of an element that has all the basic properties of the element is called a (n)
A, Electron
B. Atom
C. Nucleus
D. Isotope
Answer. B
Questions. Which of the following has no positive or negative charge?
A. Electron
B. Proton
C. Ion
D. Neutron
Answer. D
Questions . Matter that has a definite shape and is made up of tightly packed particles is classified as a
A. Solid
B. Liquid
C. Gas
D. Plasma
Answer: A
