Answer:
Only to elements are gases at room temperature and standard pressure.
Fluorine and chlorine.
Explanation:
The group 17 is called halogen.
There are five elements in halogen group.
All halogens required one electrons to complete the octet and to get the noble gas electronic configuration.
All halogen elements have seven valance electrons.
Halogen elements:
Fluorine, chlorine, Bromine, iodine and astatine
Fluorine is gas at room temperature which s 25°C and standard pressure which is 1 atm.
It is present in the from of F₂.
Chlorine is also gas at room temperature and standard pressure.
It is present in the from of Cl₂.
The bromine is liquid under these condition.
Iodine and astatine are solids.
As we move down the group their melting and boiling points increases.
Explanation:
When one atom supplies both electrons in forming a two-electron bond, it is known as a dative covalent or coordinate bond. ... In this case, the nitrogen atom has a lone pair of electrons that coordinates to the hydrogen cation, which has zero electrons, forming a covalent bond.
The answer is C.
Smoke is defined as a colloid, which is any substance consisting of particles substantially larger than atoms or ordinary molecules. It is a suspension of solid and or liquid particles in the air.
J.J. Thompson is a British physicist who discovered the electron by a series of experiments which is designed to study the nature of a cathode ray tube. His discovery showed us that an atom can be split into smaller parts. He was a pioneer in the study of the model of an atom.
