Answer:
c) atomic number / alkaline earth metals/ and halogens
Explanation:
Elements of modern periodic table are arrang in atomic number; for its electron configuration and its chemical properties. This arrangement shows periodic trends.
Alkaline earth metals are a group of elements that are located in group 2 of the Periodic Table and are the following: Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba) and Radio (Ra).
The Halogens are the chemical elements that form group 17 (XVII A, previously used) or group VII A of the periodic table: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At) and teneso (Ts)
Answer: 
kJ
Explanation:
The thermochemical equation for decomposition of ammonium nitrate is:
Given mass= 50.0 kg =
(1kg=1000g)
According to stoichiometry:
1 mole of 
gives = 82.1 kJ of heat
Thus 
of give =
kJ of heat
Thus kJ of heat is evolved from the decomposition of 50.0 kg of ammonium nitrate.
