Answer:
3. Equal numbers of protons and neutrons
Explanation:
The nucleus becomes unstable if the ratio of protons to neutrons is less than 1:1 or more than 1:1.5.
The most stable nucleus has a neutron proton ratio of 1:1 which means that they can not release a neutron or a proton to decay.
Nucleus 3 is therefore the most stable.
178.55g of H_2O are produced. When you find the molecular mass of NH_3 and O_2 and multiply them by their coefficients, you get 245.15. The law of conservation of mass states that mass can’t be created or destroyed, so this mass is the same for both the reactants and products. 245.15-66.60= 178.55. Hope this helps!
Answer:
477 nm
Explanation:
Using the expression for the energy as:
Where,
h is Plank's constant having value 
c is the speed of light having value 
is the wavelength of the light
Given, 
Also, 
So, Energy for one atom = 
Thus, applying values as:
( 1 m = 
nm )
Answer: Halogens are very reactive because they need one electron to gain a full set of valence electrons whereas noble gases already have this one electron and are extremely unstable since they have their full octet. (8 electron set) They tend to not form chemical bonds because of this.
