Carbon dioxide, when excess in number, becomes a greenhouse gas According to sources, the most probable answer to this query is that carbon dioxide is one of the greenhouse gases that traps heat affecting climate. This increase in heat turns the temperature higher. Thank you for your question. Please don't hesitate to ask in Brainly your queries.
The given question is incomplete. The complete question is :
Which of the following Group 17 elements is the least reactive
a) Flourine
b) Chlorine
c) Astatine
d) Iodine
Answer: c) Astatine
Explanation:
Halogen is the name given to Group 17 family with general electronic configuration of 
which have 7 valence electrons and thus easily gain one electron to attain stable configuration.
As we move down the group from flourine to chlorine to bromine to iodine to astatine , the valence shell moves farther from nucleus and thus tendency to accept the electron decreases and thus reactivity also decreases.
Thus Astatine is the least reactive of all.
Boiling-point<span> elevation describes the phenomenon that the </span>boiling point<span> of a liquid (a </span>solvent<span>) will be higher when another compound is added, meaning that a </span>solution has<span> a higher </span>boiling point<span> than </span>a pure solvent<span>. This happens whenever a non-volatile solute, such as a salt, is added to </span>a pure solvent<span>, such as water.
So the correct answer is C.</span>
X has valency 3 and oxide ion has valency 2
So, the formula of oxide will be X
2
O
3
Answer:
B
Explanation:
In counting the electron domains around the central atom in VSEPR theory, a Core level electron pair is not included.
Core level electron pair are the electrons other than the electrons in the valency shell of an atom. They in the proximity of the nucleus. They do not participate in the bonding.
VSEPR is the abbreviation for Valence shell Electron Pair repulsion theory. VESPR is a model for predicting molecular geometries based on the reduction in the electrostatic repulsion of the valence electrons of a molecule around a central atom.
