|
An element have atomic number 19 and mass number 39. The number of neutrons in its nucleus is |
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|
(a) |
20 |
(b) |
58 |
(c) |
19 |
(d) |
39 |
|
An element have atomic number 19 and mass number 39. The number of neutrons in its nucleus is |
|||||||
|
(a) |
20 |
(b) |
58 |
(c) |
19 |
(d) |
39 |