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प्रश्न
Fill in the following blanks with suitable words :
In water, the proportion of oxygen and hydrogen is .............. by mass.
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उत्तर
In water, the ratio of oxygen to hydrogen is 8:1 by mass.
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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
Elements having a tendency to accept electrons are called metals
WRITE SHORT ANSWER
What is radioactivity?
What are orbits or shells ?
Give two examples for each of ionic and covalent bond.
Fill in the blank
An excess of electrons produces a ________ charge.
Write the full form of IUPAC.
Why is it not possible to see an atom even with the most powerful microscope ?
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?
How many atoms are there in exactly 12 g of carbon-12 element ? (C = 12 u)
The electron shell ______ is nearest to the nucleus.
In what respects do the three isotopes of hydrogen differ? Give their structures.
Select the correct answer to the statement given below:
Imaginary path around the nucleus of an atom in which electrons revolve.
Define the following term with an example.
Non-metal
Define the following term with an example.
Metalloid
Which of the following statements made by Dalton has not undergone any change?
1 mole of Gold and Silver contain same number of atoms.
The most abundant type of atom is the universe is ______.
______ is a substance that is made up of three oxygen atoms chemically combined.
