The complete question is
Write complete symbols, including mass number and atomic number, for atoms with the following characteristics
a. Contains 28 protons and 30 neutrons
b. Contains 22 protons and 21 neutrons
c. Contains 15 electrons and 19 neutrons
d. Oxygen atom with 10 neutrons.
e. Chromium atom with a mass number of 54
Answer:
Symbol : Ni Mass number: 58 Atomic number : 28
Symbol : Ti Mass number: 43 Atomic number : 22
Symbol : P Mass number: 34 Atomic number : 15
Symbol : O Mass number: 18 Atomic number : 8
Symbol : Cr Mass number: 54 Atomic number : 24
Explanation:
The atom have a proton number of 28 and neutron number of 30. The proton number is the same as the atomic number. The atomic number of this element is 28. The mass number is the sum of proton and neutron. Therefore, the mass number is 28 + 30 = 58 The symbol with atomic number of 28 is Ni.
The proton number is same as the atomic number. That means a proton number of 22 is the same as atomic number of 22. The mass number is the sum of proton and neutron which is 22 + 21 = 43. The symbol is Ti.
Proton number is equal to electron number for an electronically neutral atom. The atomic number is 15. The mass number is 15 + 19 = 34. The symbol is P.
The oxygen atom has an atomic number of 8. The mass number is 8 + 10 = 18. The symbol is O.
Chromium atom has an atomic number of 24. The mass number is 54. The symbol is Cr.
