As has an atomic number of 33, so it has 33 protons.
It has a charge of 3-, so there are three more electrons than protons. Thus, there are 36 electrons.
It has a mass of 75, which is the sum of neutrons and protons.
33+n=75 ---> n = 75 - 33 = 42 neutrons
The answer is e) 33 protons, 42 neutrons and 36 electrons.
Answer:
The final temperature of the system is 27.3°C.
Explanation:
Heat lost by aluminum = 3.99 × 0.91 × (100-T)
= 3.631 (100-T)
Heat gained by water = 10 × 4.184 × (T-21)
= 41.84 (T-21)
As,
Heat gained = Heat loss
or, 3.631(100-T) = 41.84(T-21)
or,363.1 - 3.631 T = 41.84 T - 878.64)
or, (41.84+ 3.631) T = 878.64 +363.1
or T= 
or, T = 27.3°C
Hence the final temperature is 27.3°C.
The alkaline earth metals (the second group) because their ion charge is +2