Atom and Its Structure

Laws of Chemical Combination

In a chemical reaction, the mass of reactants and products remains constant.//रासायनिक अभिक्रिया में अभिकारकों और उत्पादों का द्रव्यमान स्थिर रहता है।

Many compounds are composed of two or more elements, and each such compound has the same elements in the same proportion, irrespective of where the compounds came from or who prepared them.///कई यौगिक दो या दो से अधिक तत्वों से बने होते हैं, और प्रत्येक ऐसे यौगिक में समान तत्व समान अनुपात में होते हैं, भले ही यौगिक कहां से आए हों या उन्हें किसने तैयार किया हो।

All matter is composed of atoms. Atoms are tiny, indivisible particles.
Atoms of a given element are identical. They have the same size, mass, and chemical properties.
Atoms of different elements are different. They have different masses and properties.
Atoms cannot be created, destroyed, or subdivided. This is a restatement of the law of conservation of mass.
Atoms combine in simple whole-number ratios to form chemical compounds. For example, water (H2O) always has two hydrogen atoms for every one oxygen atom.
In chemical reactions, atoms are combined, separated, or rearranged. The atoms themselves are not changed.

An atom consists of a positively charged sphere, and electrons are embedded in it.
The negative and positive charges are equal in magnitude. So, the atom as a whole is electrically neutral.

He proposed a model of the atom similar to that of a Christmas pudding/watermelon. (Plum Pudding Model: 1904)

In 1917, he performed the first artificially induced nuclear reaction by conducting an experiment in which nitrogen was bombarded with α-particles.
A few positively charged α-particles were deflected by small and large angles due to the presence of a heavy positive centre (Nucleus).