Basically, an electron dot diagram is just a diagram showing the number of valence electrons a certain atom has (valence electrons are electrons in the outer-most electron level of an atom). The 5 steps they give you just tell you the order of where to put each dot. The picture I attached gives a better representation.
The number around the symbol shows the order of where you would put the dot. The 1 and the 2 on the top show that the first two dots go there, and the 3, 4, and 5 go around the rest of the sides. When it gets to 6, 7, and 8, the numbers go back around to fill in each side twice.
<u>Answer:</u> The fraction of atom's mass contributed by nucleus is 0.99
<u>Explanation:</u>
Nucleons are defined as the sub-atomic particles which are present in the nucleus of an atom. Nucleons are protons and neutrons.
The isotopic symbol of Helium-4 atom is 
Number of electrons = 2
Number of protons = 2
Number of neutrons = 4 - 2 = 2
We are given:
Mass of He-4 atom = 
Mass of 1 electron = 
Calculating the mass contributed by the nucleus = 
Mass of the nucleus of He-4 atom = 
To calculate the fraction of atom's mass contributed by the nucleus, we use the equation:

Putting values in above equation, we get:

Hence, the fraction of atom's mass contributed by nucleus is 0.99
Answer:A
Explanation:
Because the water at first was not cold or warm and you want to warm it up and it’s gonna obviously be on a bowl so the taste of the bowl has a type of chemical and when you boil the water it is going to go to absorb
the water
When carbon bonds with 4 hydrogen atoms which is methane having sp3 structure so it is tetrahedral. electricity is conducted by electrons so graphite conducts by free and delocalised sea of electrons.