The atomic mass of an element is 19. The second shell of its atom contain 7 electrons. The number of protons in its nucleus is :
(1) 9
(2) 10
(3) 7
(4) 12
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The atomic mass of an element is 19. The second shell of its atom contain 7 electrons. The number of protons in its nucleus is :
(1) 9
(2) 10
(3) 7
(4) 12
The atomic mass of an element is 19. The second shell of its atom contain 7 electrons. The number of protons in its nucleus is :
(1) 9
(2) 10
(3) 7
(4) 12
Correct option (1) 9
Explanation:
Element (19/9 X)
K L
X = 2 , 7
The sum of the number of electrons in shell K & L of element X is 9
Therefore, number of protons in element X is 9.