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In hyphenated notation, we have the name of the element, a hyphen, then a number that is the sum of protons and neutrons.
The first isotope has 3 protons and 3 neutrons, so the sum is 6. Its name is lithium-6.
The second isotope has 3 protons and 4 neutrons, so the sum is 7. Its name is lithium-7.
Hope this helps!
Answer:
The number of outer shell electrons determines the group number of the element. The number of occupied principle quantum shells (energy levels) determines the period of the element. The proton number determines the element itself and its position.
Explanation:
The molarity of the NaCl in the 250 ml slat solution is 2.8M.
<h3>What is molarity?</h3>
The molarity of a solution is defined as the concentration of a solute per unit volume of the solution.
Given, the volume of the solution is 250 ml converted into l 0.25
The number of moles of NaCl is 0.70.
By the formula of molarity

Thus, the molarity is 2.8 M.
Learn more about molarity
brainly.com/question/14693949
Data:
m = 7 g
ΔT = 19 °C
Cs of water = 1 cal / g °C
Formula Q = m * Cs * ΔT
Solution:
Q = (7 g) * (1 cal / g °C) * ( 19°C) = 133 cal
Answer: two
Explanation:
Oxidation Number of Nitrogen in NO2 (Nitrogen Dioxide) Nitrogen dioxide (NO2) is a molecule which contain two oxygen atom and one nitrogen atom.