Answer:
13. Na 14. Ne. 15. U. 16. Ca. 17. C. l 18. O. 19. Cl. 20. Si 21. U 22. N.
23. Na 24. Ne. 25. U 26. Sc. 27. N 28. O 29. Cl 30. Si 31. U 32. N.
Explanation:
The general trend as you go to the right in any one period is for the size to decrease.
The general trend is that the size increases as you go down a Group.
The general trend as you go from the bottom left to the top right is a decrease in size.
Ionization energy increases as we move to the right in a period.
It decreases as we move down a group.
Going from the bottom left to top right - the ionization increases.
Answer:
No. of protons = 34
Explanation:
First we need to calculate the number of electrons in one mole of the the element:
No. of electrons per mole = Total Mass of Electrons/Mass of 1 Electron
No. of electrons per mole = (18.65 x 10⁻³ g)/(9.109 x 10⁻²⁸ g)
No. of electrons per mole = 2.04 x 10²⁵ electrons/mol
Now, we calculate the no. of electrons in 1 atom:
No. of electrons per atom = No. of Electrons per mole/No. of atoms per mole
No. of electrons per atom = (2.04 x 10²⁵ electrons/mol)/(6.022 x 10²³ atoms/mol)
No. of electrons per atom = 34 electrons/atom
Since, the no. of protons in a pure element are equal to the number of electrons. Therefore,
<u>No. of protons = 34</u>
You must see the mass of Gallium in the periodic table. The mass present there is calculated by a weighted average of the mass of the isotopes, where the weights are the abundances of each isotope. Let X the isotopic abundance of Ga⁷¹. Since there are only Ga⁶⁹ and Ga⁷¹, the isotopic abundance of Ga⁶⁹ is 1-X. Then:

I don't know the options, but probably 40% is the closest to 36.15%.
Chromium-58 Carbon-16 Nitrogen-15 Sulfer-25 Sodium-20 Selenium-80
protons:24 6 7 16 11 34
neutrons:34 10 8 7 1 46
electrons:24 6 7 16 11 34
Explanation:
<span>The atomic number of a chemical element (also known as its proton number) is the number of protons found in the nucleus of an atom of that element, It can be used to determining which group the element belongs to in the periodic table. Therefore, atomic number is the correct answer.</span>