Answer:
combustion is a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.
Answer:
The wavelength of the line in the emission line spectrum of hydrogen caused by the transition of the electron for the given energy levels is 
Explanation:
Given :
The energy E of the electron in a hydrogen atom can be calculated from the Bohr formula:

= Rydberg energy
n = principal quantum number of the orbital
Energy of 11th orbit = 

Energy of 10th orbit = 

Energy difference between both the levels will corresponds to the energy of the wavelength of the line which can be calculated by using Planck's equation.


(Planck's' equation)


The wavelength of the line in the emission line spectrum of hydrogen caused by the transition of the electron for the given energy levels is 
Isotopes of same element has different number of neutrons with different masses and having same number of protons and electrons.
Radioactive isotopes are those isotopes which are radioactive in nature. The unstable nucleus results in the radioactivity process and this process will go on until the stable isotope (element) forms.
Thus, the nucleus of unstable isotopes of an element will decay leading to emission of radiation.
<span>It affects only one chemical reaction</span>
Atomic number - 18
1s2,2s2,sp6,3s2,3p6
noble configuration is [Ne]3s2,3p6