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प्रश्न
Define the following term with an example.
Compound
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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संबंधित प्रश्न
If bromine atom is available in the form of, say, two isotopes `""_35^79Br (49.7%)" and """_35^81Br (50.3%)`, calculate the average atomic mass of bromine atom.
The average atomic mass of a sample of an element X is 16.2 u. What are the percentages of isotopes `""_8^16X" and """_8^18X` in the sample?
Tick the most appropriate answer.
Who discovered that radioactive rays are given out by uranium?
- Henri Becquerel
- Marie Curie
- Pierre Curie
- Schmidt
ANSWER IN DETAIL
State the postulates of the Dalton’s atomic theory.
ANSWER IN DETAIL
Enlist the features of Bohr’s model of an atom. How did he correct the Rutherford’s model ?
Define:- Radicals
Name two particles found inside the nucleus. What are they collectively called ?
What are orbits or shells ?
Write electronic configuration of oxygen, fluorine, sodium, silicon, argon.
What does the word ‘atom’ mean?
A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.
What is such a particle called ?
Fill in the blank
A charged particle is called an _____
Name the three subatomic particles present in an atom.
How is the size of an atom indicated ?
What is an atom ? How do atoms usually exist ?
One nm is equal to :
Deduce from the datum provided.
| Datum | To deduce |
| \[\ce{_11^23Na}\] | Neutron number |
| \[\ce{_6^14C}\] | Mass number |
| \[\ce{_17^37 Cl}\] | Proton number |
Name the gas that.
Turns moist starch iodide paper blue black.
Draw the diagrams representing the atomic structures of the following: Neon
Elements X and Y have 1 and 7 electrons in their outermost shell respectively.
Which element will gain electron?
Assertion: An atom is electrically neutral.
Reason: Atoms have equal number of protons and electrons.
Project.
To have an idea of what atoms are, students can be asked to construct atoms using pipe cleaners (thin metal wires-electron shells), pompoms (balls-different colours for protons and neutrons) and beads (electrons). Students will love and enjoy putting them together and they look great hanging from the ceiling in the classroom.
The volume occupied by 1 mole of a diatomic gas at S.T.P is ______
Atoms of different elements having ______ mass numbers, but ______ atomic numbers are called isobars.
Atoms of different elements having the same number of ______ are called isotones.
The number of atoms present in a molecule is called its ______.
Lead is also known as plumbum.
What are the 3 most abundant atoms on the earth?
The ______ are combination of atoms of various elements or the same element.
