June- July Class VII

Matter

Matter is everything around you. Matter is anything made of atoms and molecules. Matter is anything that has a mass. Matter is also related to light and electromagnetic radiation. Even though matter can be found all over the universe, you usually find it in just a few forms. Matter is anything that occupies space and has mass

Atom

An atom is made up of three particles including proton, neutron and electron. The mass of the atom is the smallest, indivisible particle of an element. Atoms of the same element are exactly alike and are different from the atoms of all other elements. Smallest particle of an element which shows all properties of element is called atom.

Some characteristics of "atoms" are as follows:

Atom takes part in chemical reactions independently.
Atom can be divided into a number of sub-atomic particles.
Fundamental particles of atom are electron, proton and neutr

Molecule

Molecules are the smallest particles of an element or compound that are made up of two or more atoms. Ions are particles that are charged due to loss or gain of electrons.

Properties of atom, Proton, Electron, Neutron.

Atom Properties

The atom above, made up of one proton and one electron, is called hydrogen (the abbreviation for hydrogen is H).  The proton and electron stay together because just like two magnets, the opposite electrical charges attract each other.  What keeps the two from crashing into each other?  The particles in an atom are not still.  The electron is constantly spinning around the center of the atom (called the nucleus).  The centrifugal force of the spinning electron keeps the two particles from coming into contact with each other much as the earth's rotation keeps it from plunging into the sun.  Taking this into consideration, an atom of hydrogen would look like this:

Proton Properties

Charge: Proton is a positively charged particle.  Magnitude of charge: Charge of proton is 1.6022 x 10-19 coulomb. Mass of proton: Mass of proton is 1.0072766 a.m.u. or 1.6726 x 10-27 kg. Comparative mass: Proton is 1837 times heavier than an electron. Position in atom: Protons are present in the nucleus of atom.

Electron

Charge: It is a negatively charged particle. Magnitutide of charge: Charge of electron is 1.6022 x 10-19 coulomb. Mass of electron: Mass of electron is 0.000548597 a.m.u. or 1.1 x 10-31 kg. Symbol of electron: Electron is represented by "e". Location in the atom: Electrons revolve around the nucleus of atom in different circular orbits. Neutron charge: It is a neutral particle because it has no charge. Mass of neutron: . Mass of neutron is 1.0086654 a.m.u. or 1.6749 x 10-27 kg.  Comparative mass: Neutron is 1842 times heavier than an electron. Location in the atom: Neutrons are present in the nucleus of an atom.