Last seen: Nov 14, 2021
(a) Water - H2O; Elements present are Hydrogen and Oxygen. (b) Ammonia - NH3; Elements present are Nitrogen and Hydrogen. (c) Methane - CH4; Ele...
A chemical formula represents the composition of a molecule of the substance in terms of the symbols of the elements present in the molecule. It is al...
(a) Oxygen = 2 (b) Ozone = 3 (c) Neon = 1 (d) Sulphur = 8 (e) Phosphorus = 4 (f) Sodium = 1
Atomicity refers to the total number of atoms present in one molecule of an element. Example: Argon is a noble gas and exists in a free state. O...
Hg – Mercury Pb – Lead Au – Gold Ag – Silver Sn – Tin
Sodium – Na Potassium – K Iron – Fe Copper – Cu Mercury – Hg Silver – Ag
Hydrogen- H, Helium-He, Lithium-Li, Beryllium-Be, Boron-B.
(a) Ca, Mg derived from English names (b) Cu, Hg derived from Latin names
The symbol of an element is either the first letter or the first and another letter of the English or Latin name of the element. Example: Oxygen is...
Yes, with the help of advanced technologies we can see atoms by using electronic microscopes. A Scanning Tunnelling Microscope (STM) can be used to pr...
Dalton’s atomic theory states that atoms are indivisible. This statement is not valid as, atoms can be further divided into electrons, protons and neu...
The major drawback of Dalton’s atomic theory is that atoms were thought to be indivisible. But, it is not true since atoms are divisible.
(a) Carbon is used as a standard for atomic mass scale. (b) Atom with 6 neutrons and 6 protons in its nucleus so that its mass number is 12. (c)...
(a) 1 : 8 (b) Conservation of mass
This means that a molecule of oxygen is 32 times heavier than 1/12 of a Carbon-12 atom.
The molecular mass of a substance is the relative mass of its molecule as compared with the mass of a Carbon-12 atom taken as 12 units.
False, the symbol of element cobalt is Co and CO is carbon monoxide.
It is impossible to see an atom even with the most powerful microscope, because they are very small.
‘nm’ represents nanometer.
The relation between nanometer and meter is 1 nanometer = 10-9 m.