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प्रश्न
What value has been given to the mass of this reference atom ?
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उत्तर
Carbon-12 atom has been given a mass of exactly 12 units (`""^12"_6C` has six protons and six neutrons).
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संबंधित प्रश्न
TRUE \ FALSE
Elements having a tendency to accept electrons are called metals
Write the names of the elements present in the following compound.
Common salt
Write the names of the elements present in the:-
Glucose
An atom has 13 protons and 14 neutrons.
What is the atomic number of the atom ?
How is the size of an atom indicated ?
What is an atom ? How do atoms usually exist ?
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?
The electronic configuration of an element Z is 2, 8, 8.
(a) What is the atomic number of the element?
(b) State whether element Z is a metal or a non-metal.
(c) What type of ion (if any) will be formed by an atom of element Z? Why?
(d) What is special about the outermost electron shell of the atom of this element?
(e) Give the name and symbol of element Z.
(f) Name the group of elements to which Z belongs.
How many atoms are there in exactly 12 g of carbon-12 element ? (C = 12 u)
The electron shell ______ is nearest to the nucleus.
Match the pairs.
| Group 'A' | Group 'B' |
| a. Proton | i. Negatively charged |
| b. Electron | ii. Neutral |
| c. Neutron | iii. Positively charged |
Draw diagrams representing the atomic structures of the following:
- Sodium atom
- Chlorine ion
- Carbon atom
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Element
Name the sub-atomic particles.
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.
1 mole of Gold and Silver contain same number of atoms.
Lead is also known as plumbum.
