Answer:
a. 3 electrons
b. 13 neutrons
c. 12 mass number
d. 10 electrons
e. 10 electrons
Explanation:
A. For an element , the atomic number of a given element is equal to the number of protons , and
For a neutral atom , the number of electrons equals the number of protons ,
Hence ,
The atomic number of Li = 3 ,
Hence ,
Number of electron for Li = 3 .
B.
Number of neutrons = mass number - atomic number ,
For Mg-25
For Magnesium , atomic number = 12 ,
Number of neutrons = 25 - 12 = 13 neutrons
C. Mass number of an element is equal to the sum of number of protons and number of neutrons ,
Hence , mass number = 5 + 7 = 12 .
D. For a negatively charged ion , add the negative charge value with the number of electrons of the neutral atom ,
For Oxygen , atomic mass = 8 ,
hence , number of electrons = 8
For O²⁻ = 8 + 2 = 10 electrons
E. For a positively charged ion , subtract the positive charge value with the number of electrons of the neutral atom ,
For Magnesium , atomic number = 12 ,
hence , number of electrons = 12 ,
for , Mg²⁺ , number of electrons = 12 - 2 = 10 electrons ,
