Answer:
A.
Explanation:
A toxic substance is a substance that can cause some harmful effects when a person is exposed to it. The sum of all adverse effects is called the toxicity of a substance. As higher is the toxicity, as dangerous is the substance. The effects can be observed in the mouth, the eyes, the skin, the tract respiratory, the brain, etc.
A substance or agent that can interfere with normal embryonic development is called teratogenic.
A substance or agent capable of causing or producing cancer in mammals is called carcinogenic.
The dose found to be lethal in 50 percent of a group of test animals when administered by the specified route is called LD50 (Lethal Dose 50).
The question is in complete, the complete question is:
Which element has an outer electron configuration of s
2
p4
?
(A) Ca (B) Cr (C) Ge (D) Se
Answer:
(D) Se
Explanation:
The outer electronic configuration of an atom reflects the group to which it belongs in the periodic table. Each group has its unique outermost electron configuration and number of electrons found in the outermost shell of the atoms of elements in the group.
s
2
p4 is the unique outermost electron configuration of group 16 elements. Group 16 elements have six electrons in their outermost shell. If we consider the options, only Se is a member of group 16. Hence it is only Se that has the outermost electron configuration s
2
p4
.
Moles=mass/Mr
mass=454
Mr=12+16+16=44
So,454/44=10.31mol
Answer is:10.31mol
