<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>
Answer:
C
Explanation:
Electromagnetic waves travel at the speed of light and do not require molecules (gas, solid or liquid) to vibrate and travel.
Soundwaves when singing or from thunder vibrate particles to reach our ears and are known as mechanical waves.
Which type of radioactive decay produces particles with the most mass? Alpha.
So that they will mix in better, or more easily. However you want to say it.
Explanation:
The molarity of a solution is defined like the number of moles of solute per liters of solution.
molarity = moles of solute/(volume of solution in L)
We know the volume of solution in L.
volume of solution = 0.65 L
To go from the mass of our solute in grams to moles we have to use its molar mass.
mass of NaCl = 63 g
molar mass of NaCl = 58.44 g/mol
moles of NaCl = 63 g * 1 mol/(58.44 g)
moles of NaCl = 1.078 moles
Finally we can find the molarity of the solution
molarity = moles of NaCl/(volume of solution)
molarity = 1.078 moles/(0.65 L)
molarity = 1.66 M
Answer: the molarity of the solution is 1.66 M.
