Although you have not provided the circled electron, I can help you with a wide explanation.
1) Atomic number of manganese is 25. That means that it has 25 protons and 25 electrons.
2) Those 25 electrons are distributed (electron configuration) as per the quantum rules:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵
3) The most reasonable is that you have been asked to give the possible quantum numbers for an electron in the 4s or 3d.
4) Those are 7 electrons and these are their possible sets of quantum numbers:
i) For the two electrons in 4s:
n is the main energy level so n = 4
l tells the kind of orbital, which is s, so l = 0
ml is also 0 (it can be from -l to + l, so given that l i s0, ml is 0)
ms: one is +/12 and the other is -1/2 (this is the spin number).
ii) For the 5 electrons in 3d
n = 3
l can be 0, 1, or 2
if l = 0, then ml = 0
if l = 1, then ml can be -1, 0 , or 1 (from - l to + l)
ms can be either +1/2 or - 1/2 (spin)
<span><em>Answer:</em>
A strontium-90 atom that has a lost two electrons has <u>38</u> protons, <u>52</u> neutrons, and <u>36</u> electrons.
<em>Explanation:
</em>Atomic number<em> of </em>Strontium (Sr) is 38.
<em>Atomic number = number of protons
</em>Hence, Strontium has 38 protons.
If the element is in neutral state,
number of protons = number of electrons.
Then, neutral Strontium atom should have 38 electrons.
But the question says Sr has lost 2 electrons. Hence, number of electrons should be 38 - 2 = 36.
Mass number = number of protons + number of neutrons.
The given mass number is 90. Hence, number of neutrons should be 90 - 38 = 52.</span>
Pluto is a dwarf planet, but one of the largest known members, in the Kuiper belt.
The Kuiper Belt extends between 30 AU and 55 AU from the Sun
(1 AU = 1.5 × 10^8 km = distance from Earth to Sun).
Pluto's orbit is highly elliptical. It ranges from 30 AU to 50 AU. When Pluto is closest to the Sun, it is inside the orbit of Neptune (30 AU).
Astronomers class Pluto as a <em>resonant Kuiper belt object</em> (KBO). Because it gets so close to Neptune, its orbit is in <em>resonance</em> with that of Neptune. Pluto makes two orbits for every three of Neptune.
<u>Answer:</u> The correct answer is Option 3.
<u>Explanation:</u>
All the radioisotope decay processes follow first order kinetics.
Rate law expression for first order kinetics is given by the equation:
where,
k = rate constant = ?
t = time taken for decay process = 8.32 seconds
a = initial amount of the reactant = 80 mg
a - x = amount left after decay process = 20 mg
Putting values in above equation, we get:
The equation used to calculate half life for first order kinetics:
where,
= half life of the reaction = ?
k = 
Putting values in above equation, we get:
Hence, the correct answer is Option 3.
Answer:
6
Explanation:
yeah i’m pretty sure 2 in the first shell and 4 in the second
