The atomic mass of an element is 19. The second shell of its atom contains 7 electrons. The number of neutrons in its nucleus is 2x. The value of x is ______.

The atomic mass of an element is 19. The second shell of its atom cont

1.	The atomic mass of an element is 19. The second shell of its atom contains 7 electrons. The number of neutrons in its nucleus is 2x. The value of x is ______.
Answer» SOLUTION :E.C. 2,7 `THEREFORE ` Z=9 , A = 19 therefore N = A -Z =10