Advertisements
Advertisements
प्रश्न
Who originated the word ‘atom’ ?
Advertisements
उत्तर
Democritus
APPEARS IN
संबंधित प्रश्न
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
Define an ionic compound.
ANSWER IN DETAIL
State the postulates of the Dalton’s atomic theory.
Write the names of `"Ca"("NO"_3)_2` compounds :
Fill in the blank
An ion with positive charge is called ______
Name two particles found inside the nucleus. What are they collectively called ?
State Dalton’s atomic theory.
Write the relation between nanometre and metre.
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 electron shell ______ is nearest to the nucleus.
State the meaning of the term – (a) atom, (b) molecule, (c) radical – with a suitable example.
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.
Rewrite the given sentence in correct form.
Elements contain two or more kind of atoms and compounds contain only one kind of atom.
State true or false. If false, correct the statement.
An atom is electrically neutral.
Atoms of different elements having ______ mass numbers, but ______ atomic numbers are called isobars.
A sample of vitamic C is known to contain 2.58 ×1024 oxygen atoms. How many moles of oxygen atoms are present in the sample?
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
The graphite refill used is pencil is made of element called ______.
______ is a substance that is made up of three oxygen atoms chemically combined.
