Question

Fill in the gaps with most appropriate word to complete the following statements:
3. All substances are made up of basic units called …...which are themselves made from three different ………… …………………
4. In the centre of an atom is the … consisting of … charged ……. and neutral ………
5. Moving around the ………. are ……… charged………..in specific energy levels you can simply envisage as ………..
6. Particular types of atoms are called ………. and all the atoms of one type have the same number of ……….. in the central ……… which is called the …………… …………..
7. Atoms are made of ………….. fundamental particles called ……………(+) ……….(0) and -------(-).
8. The mass of proton is ………. the mass of a neutron is …………. and the mass of an electron is ~ ………
9. The centre of the atom is called the ……….. It consists of …….. and neutrons and contains most of the mass of the atom.
10. The number of protons in the atom is called the ……… It also equals the number of ……….. in a neutral atom.
11. The ……….. is the sum of the protons and neutrons in the nucleus.
12. An atom of mass number 43, and atomic number 21, consists of ……… protons, ……… neutrons and …….. electrons.
13. The ……….. of an element is defined as the ………… of all the atoms present in an element compared to the mass of a carbon-12 atom (designated 12.000 atomic mass units).

Answer 1

Answer:

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