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तमिलनाडु बोर्ड ऑफ सेकेंडरी एज्युकेशनएसएसएलसी (अंग्रेजी माध्यम) कक्षा ७

Define the following term with an example. Compound - Science

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प्रश्न

Define the following term with an example.

Compound

परिभाषा
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उत्तर

Compound: A compound is a pure substance that is formed when the atoms of two or more elements combine chemically in definite proportions.

Ex: H20, NaCl.

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अध्याय 3: Matter Around Us - Evaluation [पृष्ठ ३८]

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सामाचीर कलवी Science - Term 1 [English] Class 7 TN Board
अध्याय 3 Matter Around Us
Evaluation | Q V. 4. b. | पृष्ठ ३८

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TRUE \ FALSE

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ANSWER IN DETAIL

State the postulates of the Dalton’s atomic theory.


Define:- Atom


Define:- Radicals


 Name the particles which revolve around the nucleus.


An atom has 13 protons and 14 neutrons.

What is the atomic number of the atom ?


A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.

What is the atomic numebr of X ?


Name the unit in which the radius of an atom is usually expressed.


An atom of element E contains 3 protons, 3 electrons and 4 neutrons :
(a) What is its atomic number?
(b) What is its mass number?
(c) Write the electronic configuration of the element E.
(d) State whether element E is a metal or non-metal. Why?
(e) What type of ion, cation or anion, will be formed by an atom of element E? Why
(f) Write the symbol of the ion formed by an atom of element E.
(g) What could element X be?


In what respects do the three isotopes of hydrogen differ? Give their structures.


A radical take part – unsplit in a chemical reaction and retains its identity in reactions.
With reference to the radical –

  1. ammonium
  2. bisulphate
  3. carbonate

state the group of atoms present in each radical.


The electronic structure [configuration] of fluorine can be written as 2, 7. In a similar way give the electronic configuration of phosphorus


Define the following term with an example.

Non-metal


An element is composed of ______ atoms.


1 mole of Gold and Silver contain same number of atoms.


Give the salient features of “Modern atomic theory”.


Which of the following has maximum number of atoms?


Dalton’s atomic theory successfully explained

(i) Law of conservation of mass

(ii) Law of constant composition

(iii) Law of radioactivity

(iv) Law of multiple proportions


Atomic models have been improved over the years. Arrange the following atomic models in the order of their chronological order

  1. Rutherford’s atomic model
  2. Thomson’s atomic model
  3. Bohr’s atomic model

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