We first assume that the gas is ideal which is a safe assumption to approximate the answer to the problem. Then we need to know the ideal gas equation and that is:
PV=nRT
where
P- pressure
V- volume
n-number of moles-
R- ideal gas constant
T-temperature.
Since we know that P, T and V are constant, rearranging the equation would lead to:
P/TR = n/V or the ratio of the moles of gas and volume is constant.
(3moles)/2L = (3+x)/4L
where
x is the additional moles.
Solving for x = 3 moles.
Protons = +1
negatrons = -1
neutrons = 0
<span>electrons = -1
</span>
<span>negatrons are like positrons and they are subatomic particles and are not present in atoms
</span>
so electrons are negatively charged and are present in atoms
hope that helps
Answer: Mercury-194 is an unstable isotope and hence is radioactive.
Explanation: Mercury-194 is an isotope of mercury, having formula 
Number of protons in this isotope = 80
Number of neutrons in this isotope = 114
This isotope is radioactive in nature and under decay process by Electron Capture.
Electron capture reactions are the reactions in which a proton in a nucleus absorbs an electron and convert it into neutron. The resulting nucleus will have a decreased atomic number and same atomic mass.
Reaction for electron capture of mercury-194 follows:

that would have to be nucleus
A chemical bond that involves the transfer of electrons from a metal to a nonmetal and thus forms ions and the atoms in the molecule are attracted towards each other through electrostatic force of attraction are said be ionic bond. In short, the bond formed between the two oppositely charged ions.
In salt, the compound formed between sodium and chlorine is sodium chloride having molecular formula
where sodium is a metal and chlorine is the non-metal. The formation of the compound takes place by transfer of an electron from sodium thus forming a cation of formula
to chlorine which gains electron and thus results in an anion formation having formula
. The force of attraction between these oppositely charged ions that helds them together and results in formation of
compound is electrostatic force of attraction.
Hence in salt, the nature of bond between sodium and chlorine is ionic.