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An element has an atomic number of 78. The number of protons and electrons in a neutral atom of the element are

  1. 78 protons and 0 electrons.

  2. 78 protons and 39 electrons.

  3. 156 protons and 78 electrons.

  4. 39 protons and 39 electrons.

  5. 78 protons and 78 electrons.

Answer:

E

The number of protons an element has is called the atomic number. In a neutral atom, there are the same number of protons and electrons.