Advertisements
Advertisements
प्रश्न
The average atomic mass of a sample of an element X is 16.2 u. What are the percentages of isotopes `""_8^16X" and """_8^18X` in the sample?
Advertisements
उत्तर
It is given that the average atomic mass of the sample of element X is 16.2 u.
Therefore,
The atomic mass of the given element X is = 16.2 u.
Let `""_8^16 X` percentage = a
Then `""_8^18X` percentage = (100 − a)
Average mass of X = `16("a"/100) + 18((100 - "a")/100)`
16.2 = `((16"a")/100) + ((1800 - 18"a")/100)`
1620 = 1800 − 2a
1800 - 1620 = 2a
180 = 2a
a = `180/2`
a = 90
Therefore `""_8^16X"` percentage = 90%
And `""_8^18X"` percentage = 100 − 90
= 10%
APPEARS IN
संबंधित प्रश्न
Write the names of `"FeS"` compounds :
Write electronic configuration of oxygen, fluorine, sodium, silicon, argon.
State Dalton’s atomic theory.
Name the particle or particles you would expect to find in :
The orbit of an atom
Define: An Atom:
Fill in the blank
If an atom gains an electron, it is called an _______
Write the relation between nanometre and metre.
How many atoms are there in exactly 12 g of carbon-12 element ? (C = 12 u)
Compare:
Chlorine atom and chloride ion, with respect to
Atomic structure
Electrical state
Elements X and Y have 1 and 7 electrons in their outermost shell respectively.
Which element will lose electron?
Draw the basic structure of an atom representing its –
- Subatomic particles
- Nucleus
- Orbits or shells.
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.
Define the following term with an example.
Metal
The number of atoms present in a molecule is called its ______.
1 mole of Gold and Silver contain same number of atoms.
Dalton’s atomic theory successfully explained
(i) Law of conservation of mass
(ii) Law of constant composition
(iii) Law of radioactivity
(iv) Law of multiple proportions
The smallest unit of an element is ______.
______ is a substance that is made up of three oxygen atoms chemically combined.
An atom of Oxygen (O) and two atoms of hydrogen (H.) combine to form a molecule of ______.
