8.................................
Answer:
4
Explanation:
Relationship between wavenumber and Rydberg constant (R) is as follows:

Here, Z is atomic number.
R=109677 cm^-1
Wavenumber is related with wavelength as follows:
wavenumber = 1/wavelength
wavelength = 253.4 nm

Z fro Be = 4

Therefore, the principal quantum number corresponding to the given emission is 4.
It turns chemical into electricity
Answer:
Neutrons.
Explanation:
Isotopes can be defined as the atom of an element that has the same number of protons but different number of neutrons. This ultimately implies that, the isotopes of an element have the same atomic number (number of protons) but different atomic mass (number of nucleons).
The isotope of an element is denoted by
Where; X is the symbol of the element.
A is the atomic mass or number of nucleons.
Z is the atomic number or number of protons.
<em>Therefore, the number of neutrons = A - Z</em>
<em>Isotopes of carbon differ with respect to the number of neutrons.</em>
<em>Basically, there are three (3) Isotopes of Carbon and these are;</em>
<em>1. Carbon-12: it has an atomic mass of 12 with 6 numbers of proton and neutron respectively. </em>
<em>2. Carbon-13: it has an atomic mass of 13 with 6 numbers of proton and 7 numbers of neutron. </em>
<em>3. Carbon-14: it has an atomic mass of 14 with 6 numbers of proton and 8 numbers of neutron. </em>
Answer:
N₂ + 3H₂ → 2NH₃ ΔH = - 92.2KJ
Explanation:
Let's write out the chemical equation between Nitrogen and Hydrogen to Form Ammonia.
Nitrogen + Hydrogen = Ammonia
N₂ + H₂ → NH₃
A Thermochemical Equation is a balanced stoichiometric chemical equation that includes the enthalpy change, ΔH.
The balanced stoichiometric chemical equation is given as;
N₂ + 3H₂ → 2NH₃
92.2 kJ of energy are evolved for each mole of N2(g) that reacts. And from the equation, 1 mole of N2 reacts.
The enthalpy change, ΔH = - 92.2KJ. The negative sign is because heat is being evolved.
The balanced thermochemical equation;
N₂ + 3H₂ → 2NH₃ ΔH = - 92.2KJ