Notes of chemistry 1 topic wise ch structure of atom
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Answer:
Matter is made up of tiny particles called atoms. Atoms are further made of three fundamental particles or sub – atomic particles called electron, proton and neutron.
Earlier Dalton postulated that atom is indivisible i.e. cannot be further divided which proved to be wrong by discovery of sub – atomic particles.
Sub-atomic particles of atom includes
(a) Electrons – negatively charged with charge of –1 and negligible mass.
(b) Protons – Positively charged with charge of +1 and mass is 1 u.
(c) Neutrons – Particles are with no charge and mass of 1 u.
Thomson’s model of an atom
• Atom is electrically neutral consisting of positively charged sphere with electrons embedded in it.
• If failed to explain the results of experiments carried out by other scientists.
Bohr’s model of an atom
• An atom has a positively charged nucleus and electrons revolve in permitted circular orbits with fixed radii and energy.
• Bohr explained the drawback of Rutherford’s model of an atom.
Rutherford’s model of an atom
• He performed the α-particle scattering experiment and proposed that an atom is electrically neutral, with a positively charged nucleus having protons and neutrons and negatively charged electrons revolving around the nucleus.
Bohr-Bury scheme
• The number of electrons that can be present in a given shell is 2n2, when ‘n’ is the number of shell.
• Maximum number of electrons in the outermost orbit should not exceed 8.
Valency
• The combining capacity of the atoms of an element is valency.
• Elements having 1, 2, 3, and 4 electrons in the valence shell, has valency equal to number of electrons.
• Elements having more than 4 electrons in the valence shell has valency equal to 8 minus the number of valence electrons.
Atomic number and mass number
• Atomic number (z) is number of protons in one atom of an element.
• Mass number (A) is the sum of protons and neutrons present in the atom of the element.
• Notation for an atom
Isotopes
• Isotopes are the atoms of the same element, having the some atomic number but different mass number.
• Isotopes are useful as nuclear fuel, in medical field, in carbon dating, etc.
Answer:
everything in universe that occupies space scientist name latest matter are there are three types of matter subtropics and electrons and protons and neutrons