1p is not possible because it goes like this 1s2 2s2 2p6
D. toxic chemical used to control pest population.
Answer:
a) Explain why:
(i) All the elements of a group have similar chemical properties.
(ii) All the elements of a period have different chemical properties.
(b) The atomic radii of three elements X, Y and Z of a period of the periodic table are 186 pm, 104 pm and 143 pm respectively. Giving a reason arrange these elements in the increasing order of atomic number in the period.
The muscular and skeletal system because we use our brain to move our body it sends a signal to move that muscle that we want to use
Answer:
Carbon
Explanation:
the answer gives you 12.011 which is closer to the amu of carbon