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Question
Fill in the following blanks with suitable words :
In water, the proportion of oxygen and hydrogen is .............. by mass.
Solution
In water, the ratio of oxygen to hydrogen is 8:1 by mass.
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RELATED QUESTIONS
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
TRUE \ FALSE
Neils Bohr gave the theory to explain the arrangement of protons in an atom.
WRITE SHORT ANSWER
What is radioactivity?
Write the names of the elements present in the following compound.
Common salt
Write the names of the elements present in the:-
Ammonia
Write the names of `"FeS"` compounds :
How did Neils Bohr visualise the atom ?
Define the following term:
Atom
Elements X and Y have 1 and 7 electrons in their outermost shell respectively.
Which element will lose electron?
Elements X and Y have 1 and 7 electrons in their outermost shell respectively.
Which will form positive ion?
A radical take part – unsplit in a chemical reaction and retains its identity in reactions.
With reference to the radical –
- ammonium
- bisulphate
- carbonate
state the group of atoms present in each radical.
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.
Does the solubility of a substance change with temperature? Explain with the help of an example.
Atomic models have been improved over the years. Arrange the following atomic models in the order of their chronological order
- Rutherford’s atomic model
- Thomson’s atomic model
- Bohr’s atomic model
Write any two observations which support the fact that atoms are divisible.
The smallest unit of an element is ______.
An atom of Oxygen (O) and two atoms of hydrogen (H.) combine to form a molecule of ______.
What are the 3 most abundant atoms on the earth?
