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प्रश्न
Define the following term with an example.
Metalloid
उत्तर
Metalloid: Metalloid is a chemical element that exhibits some properties of metals and some of non-metals. Metalloids are generally semi-conductors.
Ex.: Silicon. Arsenic, Antimony and Boron.
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संबंधित प्रश्न
Tick the most appropriate answer.
Who discovered that radioactive rays are given out by uranium?
- Henri Becquerel
- Marie Curie
- Pierre Curie
- Schmidt
MATCH THE COLUMNAS
| 1. Jpham Dalton | a. Neutrons |
| 2. Atom | b. Model of the atom |
| 3. Chadwick | c.The atomic theory of matter |
| 4. Rutherfrod | d. Positively charged |
| 5. Protons | e. Electricity neutral |
| 6. Nuclear fusion | f. Generator of electricity |
| 7.Gamma -rays | g. High penetrating power |
| h.Energy in sun |
TRUE \ FALSE
Elements having a tendency to accept electrons are called metals
WRITE SHORT ANSWER
What is radioactivity?
ANSWER IN DETAIL
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Write the names of `("NH"_4)_2"SO"_4` compounds:
Define: Ions
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Give the charge and the mass of an electron, proton and neutron present in an atom ?
An atom has 13 protons and 14 neutrons.
What is the atomic mass of the atom ?
A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.
Does the particle have an excess of electrons or a deficiency of electrons ?
Name the three subatomic particles present in an atom.
Why is it not possible to see an atom even with the most powerful microscope ?
How many times is a proton heavier than an electron?
State two observations which show that atom is not indivisible.
An atom of an element X may be written as `""_9^4"X"`
(a) What does the figure 9 indicate?
(b) What does the figure 4 indicate?
(c) What is the number of protons in atom X?
(d) What is the number of neutrons in atom X?
(e) What is the number of electrons in atom X?
(f) How many electrons are there in the outermost shell of an atom of element X?
(g) Write the symbol of ion formed by an atom of element X.
Give scientific reason.
All the mass of an atom is concentrated in the nucleus.
Define the following term:
Atom
Electron, proton, neutron are the types of ______ in an atom.
The electronic structure [configuration] of fluorine can be written as 2, 7. In a similar way give the electronic configuration of phosphorus
State true or false. If false, correct the statement.
The basic unit of an element is molecule.
K: Potassium:: C: ______.
Name the sub-atomic particles.
Define the following term with an example.
Metal
Which of the following statements made by Dalton has not undergone any change?
In the nucleus of `""_20"Ca"^40`, there are ______
Give the salient features of “Modern atomic theory”.
A change in the physical state can be brought about
