CHEMISTRY 4

CHEMISTRY 4

1. the nucleus of an atom is made up from protons and neutrons

2. If a neutral atom has an atomic number of 11 and a mass number of 23 it will be sodium and have : 11 protons(because of its atomic number and 11 electrons( the same amount of protons.it will have 12 neutrons making a mass number of 23

   • to get neutrons take the protons away from the mass number

3. elements with the same atomic number but different mass numbers are isotopes

4. An atom is neutral because it has an equal amount of electrons and protons. the positive charges balance out the negative

5. the different numbers of neutrons in isotopes can be deduced.

6. an element with an electronic structure of 2.8.6 has three electron shells so is in group 3