Atomic structure

71.An atom has 9 electrons and 10 neutrons, its mass number will be
 
A. 9
 
B. 10
 
C. 18
 
D. 19
 
Option”D” is correct
72.The number of neutrons and protons in the nucleus of ₈₈Ra²²⁶ (radium) are respectively
 
A. 138 and 88
 
B. 88 and 138
 
C. 226 & 88
 
D. 88 and 226
 
Option”A” is correct
73.The element which has 2 protons, 2 neutrons and 2 electrons in its atom, what will be the mass number of that element?
 
A. 2
 
B. 4
 
C. 6
 
D. 8
 
Option”B” is correct
74.The number of electrons in ₁₉K⁴º is –
 
A. 18
 
B. 19
 
C. 20
 
D. 10
 
Option”B” is correct
75.If the third orbit of an atom is the outermost orbit, then the maximum number of electrons it can hold is
 
A. 8
 
B. 16
 
C. 18
 
D. 36
 
Option”C” is correct
76.The atomic number of an atom is Z and its mass number is M, then what will be the number of neutrons in its nucleus?
 
A. M+Z
 
B. M-Z
 
C. M x Z
 
D. M/Z
 
Option”B” is correct
77.A chlorine atom of atomic number 17 and mass number 35 has in its nucleus
 
A. 18 protons
 
B. 18 neutrons
 
C. 35 protons
 
D. 35 neutrons
 
Option”B” is correct
78.Which of the following electronic configuration is not possible?
 
A. 1s²
 
B. 1s², 2s²2p⁶2d¹º,3s²
 
C. 1s², 2s²2p⁵
 
D. 1s², 2s²2p⁶2d¹º,3s¹
 
Option”B” is correct
79.What is the electronic configuration of 1s², 2s²2p⁶?
 
A. Na and Ne
 
B. Ne and Na⁺
 
C. Ne and F
 
D. Na+ and F
 
Option”B” is correct
80.The electronic configuration of an atom with atomic number 20 is –
 
A. 2,8,10
 
B. 2,6,8,4
 
C. 2,8,8,2
 
D. 2,10,8
 
Option”C” is correct