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प्रश्न
Define: An Atom:
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उत्तर
An Atom: Smallest particle of an element that can exist and have properties of an element.
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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.
Tick the most appropriate answer.
Who discovered that radioactive rays are given out by uranium?
- Henri Becquerel
- Marie Curie
- Pierre Curie
- Schmidt
TRUE \ FALSE
Cathode rays are a stream of fast moving particles that travel in random directions.
Fill in the blank:
Atoms are _____
Define: Mass number
Name the particle or particles you would expect to find in :
The orbit of an atom
An atom has 13 protons and 14 neutrons.
What is the atomic mass of the atom ?
Fill in the blank
A charged particle is called an _____
Fill in the blank
A deficiency of electrons produces a ________ charge.
How is the size of an atom indicated ?
Dalton's atomic theory says that atoms are indivisible. Is this statement still valid ? Give reasons for your answer.
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.
Calculate the number of moles in 12.044 × 1025 atoms of phosphorus.
Draw diagrams representing the atomic structures of the following:
- Sodium atom
- Chlorine ion
- Carbon atom
- Oxygen ion
Elements X and Y have 1 and 7 electrons in their outermost shell respectively.
Which will form negative ion?
Define the following term with an example.
Compound
In all atoms of an element
Define the term ions or radicals.
Lead is also known as plumbum.
