Whatever be the physical states of matter, they are made up of large number of extremely small particles which may be atoms or molecules.
Atoms
An atoms is the smallest unit of an element which takes part in the chemical reaction. There are many kinds of atoms as there are elements. Atom may or may not be capable of independent existence. Previously atom was considered to be the ultimate particle of matter which can not be subdivided. But now it is known that atom consists of still smaller particles called electrons, protons, and neutrons. These particles are known as sub-atomic particles. These sub-atomic particles are arranged in some particular manner in an atom. Thus atom has its own structure. Atom consists of positively charged nucleus around which negatively charged electrons revolve like planets round the sun The nucleus contains positively charged protons and chargeless neutrons. These particles together are known as nucleons. The mass of the atom is mainly due to these nucleons.
Atomic weight
Atom is an extremely small particle. If you buy gold out of 1 paisa it will contain more atoms of gold than the number of human beings in the world. The atom, even though very small, has mass. The gram is very big unit to measure the mass of an atom. So scientists have devised a new unit known as atomic mass unit to measure the mass of an atom. In atomic mass unit the mass of hydrogen is equal to 1.008. One atomic mass unit is nearly equal to 1.661 multiply by 10th power -24 gm. which is in fact the mass of 1/12th the mass of ordinary carbon atom.
Atomic mass or weight is the average mass per atom of the element in atomic mass unit. These days atomic mass unit is called dalton in honour of John Dalton who put forward the first Atomic Theory based on scientific reasoning.
Molecules
A molecule is the smallest unit of an element or a compound which is capable of independent existence. A molecule of an element contains only one kind of atoms while a molecule of compound contains at least two kinds of atoms. For example, a molecule of hydrogen contains two atoms of hydrogen. Hence hydrogen is taken as an element. On the other hand a molecule of water contains two atoms of hydrogen and one atom of oxygen. Hence water is taken as a compound. A molecule of ozone contains three atoms of oxygen and a molecule of helium contains one atom of helium.
Molecular weight
Molecular mass or weight is the mass of the molecule in atomic mass unit. The molecular mass can be calculated by adding the atomic masses of constituent atoms in the molecule. The molecular mass of water is 18. This is obtained by adding the mass of two hydrogen and one oxygen atoms.
Atoms
An atoms is the smallest unit of an element which takes part in the chemical reaction. There are many kinds of atoms as there are elements. Atom may or may not be capable of independent existence. Previously atom was considered to be the ultimate particle of matter which can not be subdivided. But now it is known that atom consists of still smaller particles called electrons, protons, and neutrons. These particles are known as sub-atomic particles. These sub-atomic particles are arranged in some particular manner in an atom. Thus atom has its own structure. Atom consists of positively charged nucleus around which negatively charged electrons revolve like planets round the sun The nucleus contains positively charged protons and chargeless neutrons. These particles together are known as nucleons. The mass of the atom is mainly due to these nucleons.
Atomic weight
Atom is an extremely small particle. If you buy gold out of 1 paisa it will contain more atoms of gold than the number of human beings in the world. The atom, even though very small, has mass. The gram is very big unit to measure the mass of an atom. So scientists have devised a new unit known as atomic mass unit to measure the mass of an atom. In atomic mass unit the mass of hydrogen is equal to 1.008. One atomic mass unit is nearly equal to 1.661 multiply by 10th power -24 gm. which is in fact the mass of 1/12th the mass of ordinary carbon atom.
Atomic mass or weight is the average mass per atom of the element in atomic mass unit. These days atomic mass unit is called dalton in honour of John Dalton who put forward the first Atomic Theory based on scientific reasoning.
Molecules
A molecule is the smallest unit of an element or a compound which is capable of independent existence. A molecule of an element contains only one kind of atoms while a molecule of compound contains at least two kinds of atoms. For example, a molecule of hydrogen contains two atoms of hydrogen. Hence hydrogen is taken as an element. On the other hand a molecule of water contains two atoms of hydrogen and one atom of oxygen. Hence water is taken as a compound. A molecule of ozone contains three atoms of oxygen and a molecule of helium contains one atom of helium.
Molecular weight
Molecular mass or weight is the mass of the molecule in atomic mass unit. The molecular mass can be calculated by adding the atomic masses of constituent atoms in the molecule. The molecular mass of water is 18. This is obtained by adding the mass of two hydrogen and one oxygen atoms.
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