Mercury is classified as an heavy metal
Answer:
The area around the nucleus must be of low mass.
Explanation:
Rutherford`s experiment showed that there are some positive charges in the center of the atoms, and because they are all together, they will give a great mass to the atom.
It was quite different from Thomson`s experiment, in which it was thought that the negative charges were mixed with the positive charges, around the atom (like a Pudding Model). In Rutherford`s experiment, because the direction of beta particles, it was the prediction of the positive nucleus.
Hope this info is useful.
<u>Answer:</u>
<em>The rule is called as Octet Rule.</em>
<u>Explanation:</u>
Chemical bond: the attractive force which holds the atoms together in a molecule. Except noble gases He,Ne,Ar,Kr and Rn all other atoms have less than 8 electrons in its outer shell and unstable.
In order to attain stability Atoms loses or gains or shares electron to get 8 electrons in its outer shell which is called noble gas configuration.
“Octa” means 8.
The respectable gases are the main arrangement of components that have 8 electrons in their furthest shells and that is the reason they are steady and lifeless. The octet principles express that a component must have 8 electrons in its furthest shell as to be steady.
Noble gas is very unreactive, it seldom form compound with other elements unless in extreme pressure and temperature. It is because noble gas has a stable duplet or octet of electron, it has low tendency to lose or gain electrons. Therefore it is very unreactive
Answer:
B. Ca
Explanation:
Let's look at the electron configurations of all four elements (I am going to write it in noble gas configuration to make it simpler):
Mg electron configuration: [Ne]3s2
Ca electron configuration: [Ar]4s2
Ar electron configuration: [Ar]
K electron configuration: [Ar] 4s1
We notice that Ca has two electrons in the 4s sublevel, which satisfies what the question is asking for.
The answer is thus B. Ca.