Which of the following element is used in the treatment of cancer?
21H and 31H are _______ .
Atoms of the same element having the same atomic numbers but different mass numbers are termed as isotopes.
Which one of the following statements is correct about isotopes?
The two isotopes of chlorine are 3517Cl and 3717Cl in the ratio of 3:1. What is the average atomic mass of the chlorine atom?
Average atomic mass of chlorine is given by:
(35 x 3) + (37 x 1)/4 = 35.50 u
Which one of the following statements is incorrect?
Argon has atomic number of 18 and mass number of 40. Calcium has atomic 20 and mass number 40. Calcium and argon are examples of _______.
Atoms of different elements with different atomic numbers and the same mass number are known as isobars.
The isotopic composition of a certain element X is 80% 24X, 10% 25X and 10% 26X. The relative-atomic mass of X is _______.
Atomic number is equal to:
Why do isotopes have different physical properties?
They have similar chemical properties because isotopes of an element have the same number of electrons as an atom of that element. The electron arrangement is the same owing to same chemical properties. However they have different numbers of neutrons, which affects the mass number. Mass number determines the physical properties such as boiling/melting/density etc
An element B has 5 protons and 6 neutrons. What will be the symbol of the element B?
Atomic number of B = Number of Protons = Number of electron in element
Mass number = Number of protons + Number of neutrons = 5 + 6 = 11
So, symbol of B : 115B
The atomic number of an element having mass number 23 and number of neutron 12 is ________.
Which form of iodine is used for the treatment of goiter?
The total number of neutrons in 1224Mg2+is:
Neon occurs as two isotopes of mass numbers 20 and 22. Its relative atomic mass is 20.2. What is the percentage of 20Ne in naturally occurring neon?
Let the relative abundance% of Ne -20 = x1
So, relative abundance% of Ne -22 = x2
Now, we know that atomic mass = sum of relative abundance in atomic mass of each isotope / 100%
20.2 = 20 x1 + 22 x2 / x1 +x2
20.2 x1 + 20.2x2 = 20x1 + 22x2
0.2x1 = 1.8 x2
x1 / x2 = 1.8/ 0.2 = 9/1 ( relative abundance)
x1% = 9/10 * 100 = 90% lighter isotopes
x2% = 1/ 10* 100 = 10% heavier isotope
Which of the following elements has 17 electrons and 17 protons?
The atomic number is the number of electrons present in an atom. We know that an atom has the same number of electrons & Protons. Therefore Chlorine is the element that has 17 protons. Hence the element is Chlorine.
Find the symbol of an element X, if its mass number is A and atomic number is Z respectively.
The atomic number and the mass number of an element A are 14 and 28 respectively. The number of neutrons are:
Given, Z = 14 , A = 28 ;
We know that Z = p=14
And, A = p + n ⇒ 28 = 14+n
n = 28 -14
n = 14
Hence, no. Of neutrons are 14.
Which of the following statement is correct for isotopes?
An neutral element A has 3 electrons, the atomic number of an element is _______.
An atom is represented by symbol 2314M. What does the number 23 represent?