Element
Element: An element is a substance that consists of only one type of atom.Each element is assigned a unique chemical symbol, such as "O" for oxygen, "H" for hydrogen, and "Fe" for iron.
Elements cannot be broken down into simpler substances by chemical reactions. Examples of elements include oxygen gas (O2), iron (Fe), and gold (Au).
Most of the elements are naturally occurring, while a few are synthetic, Which is developed in laboratories through nuclear reactions. However, both naturally occurring and synthetic elements follow the same principles of chemistry.
In nature, elements are found in solids, liquids, and gases, and they make up the building blocks of all matter on Earth. Examples of natural elements are oxygen (O), hydrogen (H), carbon (C), nitrogen (N), and iron (Fe). They are abundant in the Earth's crust, oceans, atmosphere, and living organisms.
Each element is composed of similar kinds of atoms .They have protons and Neutrons in their atomic nucleus and electrons revolve around nucleus. The number of protons defines the element chemical properties and is called the atomic number.
There are 118 elements in the periodic table. Some elements beyond 118 have been synthesized in laboratories, but they are highly unstable and exist only for very short periods of time before decaying into other elements.
Elements are arranged in the periodic table to make study easy of its properties where elements with similar properties are grouped together. The periodic table categorizes elements based on their atomic number, electron configuration, and chemical properties.
Elements exist in multiple forms. They are called isotopes, which have the same number of protons but different numbers of neutrons. They have the same chemical properties but may have different physical properties, such as mass or stability.
Some examples of isotopes:
1. Hydrogen:
- Protium (H1): 1 proton, 0 neutrons
- Deuterium (H2 or D): 1 proton, 1 neutron
- Tritium (H3 or T): 1 proton, 2 neutrons
2. Carbon:
- Carbon-12 (C12): 6 protons, 6 neutrons
- Carbon-13 (C13): 6 protons, 7 neutrons
- Carbon-14 (C14): 6 protons, 8 neutrons
3. Uranium:
- Uranium-235 (U235): 92 protons, 143 neutrons
- Uranium-238 (U238): 92 protons, 146 neutrons
4. Oxygen:
- Oxygen-16 (O16): 8 protons, 8 neutrons
- Oxygen-17 (O17): 8 protons, 9 neutrons
- Oxygen-18 (O18): 8 protons, 10 neutrons.
Some group of elements in the the periodic table that have different atomic numbers but their mass number are the same. They are called isobars .They have different number of protons in their nucleus but the sum of the number of protons and neutrons is the same.
For example, Argon (18Ar40), Potassium (19K40), and Calcium (20Ca40) are isobars
They have 40 as their mass number but their atomic number are different. This is because they have different atomic numbers but the sum of protons and neutrons in their nucleus is different.
Valency:
Combining capacity of an element is known as its valency.
Valency is equal to the number of electrons gained, lost or shared by an atom of an element to achieve the nearest noble gas configuration.
Compound
When two or more elements combine chemically in a fixed ratio by mass, the obtained product is called a compound. This means a substance up made of two or more different elements which are chemically joined is called Compound.
One example of compound is water (H2O), which is made up of elements 2 atoms of hydrogen element and 1 atom of oxygen element and these 3 atoms are chemically joined .
The molecule is the simplest form of the compound. There are two types of compounds : covalent compound and ionic compound (Electrovalent compound).
Different elements react with each other and form strong bonds (chemically joind) a form compound. Significant amount of energy is required to break apart.
A compound is identified by its name and chemical formula.
Example:
Hydrogen chloride: (HCl)
Magnesium sulfate :(MgSO4)
Sodium bicarbonate : (NaHCO3)
