Roughly, Aufbau Principle says that in an atom or an ion, electrons enter the shell with low energy first before entering the shell with high energy.
An atom has shells around its nucleus. Electrons enter these shells and orbit around the nucleus of an atom. To say about the properties of these shells, the shell nearest to the nucleus has the lowest energy. The farther the shell from the nucleus, the higher its energy. Aufbau Principle states that electrons enter the closest shell to the nucleus first since it has the lowest energy. When that shell has its maximum number of electrons is can hold, then the next electron will enter the second-closest shell to the nucleus, which has higher energy than the first shell.
The answer is D the oldest layer
Answer:
The presence of Br atom produces 2 ions (M and M+2) with the same abundance.
Explanation:
Mass spectrometry is an instrumental technique in which chemical substances are ionized and fragmented. The nature of the substances produce different fragmentations.
A way to know if a substance contains bromine is seeing the parent molecular ion (M, Subtance with ⁷⁹Br) and M+2 (Substance with ⁸¹Br) with the same relative abundance. Where parent molecular ion is the substance without fragmentations
<em>That is because in nature, the isotope abundance of bromine is ⁷⁹Br with 51% and ⁸¹Br with 49%, producing the 49% of ions having 2 units of m/z higher than its consecutive ion.</em>
Explanation :
Isotope : It is defined as the element that have the same number of protons but have the different number of neutrons of each of the atom.
Atomic number is defined as the number of protons or number of electrons.
Atomic number = number of protons = number of electrons
Mass number is defined as the sum of number of protons and number of neutrons.
Number of neutrons = Mass number - Number of protons
For the given options:
(a) 
Atomic number = 5
Number of proton = 5
Number of electron = 5
Atomic mass = 10
Number of neutrons = Atomic number - Number of protons
Number of neutrons = 10 - 5 = 5
(b) 
Atomic number = 80
Number of proton = 80
Number of electron = 80
Atomic mass = 199
Number of neutrons = Atomic number - Number of protons
Number of neutrons = 199 - 80 = 119
(c) 
Atomic number = 29
Number of proton = 29
Number of electron = 29
Atomic mass = 63
Number of neutrons = Atomic number - Number of protons
Number of neutrons = 63 - 29 = 34
(d) 
Atomic number = 6
Number of proton = 6
Number of electron = 6
Atomic mass = 13
Number of neutrons = Atomic number - Number of protons
Number of neutrons = 13 - 6 = 7
(e) 
Atomic number = 34
Number of proton = 34
Number of electron = 34
Atomic mass = 77
Number of neutrons = Atomic number - Number of protons
Number of neutrons = 77 - 34 = 43
Answer:
The Molarity of KOH is

Explanation:
The endpoint indicates the volume necessary to neutralize the moles of acid.
In other words, the point at which the moles of both solutions are the same.

we match these equations and find the concentration of KOH

