if I'm not mistaking it would be the second option
Answer:
The correct answer is periods. See the explanation below, please.
Explanation:
The horizontal lines in the periodic table are called periods (ranging from 1 to 7) and vertical lines (ranging from 1 to 18).
The period that an element belongs to coincides with the last electronic layer of the element (that compound in period 3 will have 2 electronic layers).
Answer:
The correct option is the option;

Explanation:
The wavelength of a wave is the distance between two successive crests of the wave
Therefore, the wavelength, λ, is given by the fraction of the velocity, <em>v</em>, of the wave divided by the frequency, <em>f</em>, (the number of cycles that pass through a point) of the wave
Mathematically, we have;


Freezing point depression depends of the number of particles of the solute in the solution.
1)Pure water have highest freezing point. All other solutions with given solutes will have lower temperatures.
2) The more particles of the solute in the solution the lower freezing point is going to be.
<span>b. 1.0 m NaCl ( dissociates and give 2 mol ions (1 mol Na⁺ and 1 mol Cl⁻))
c. 1.0 m K3PO4 (</span>dissociates and give 4 mol ions (3 mol K⁺ and 1 mol PO4³⁻)<span>
d. 1.0 m CaCl2 (</span>dissociates and give 3 mol ions (1 mol Ca²⁺ and 2 mol Cl⁻))<span>
e. 1.0 m glucose (c6h12o6) (glucose does not dissociate, and solution have
1 mole of particles of the solute(glucose))
The largest number of particles has </span>1.0 m K3PO4 solution, and it is has lowest freezing point . Answer is C.
D. I or Iodine
This is because they are both in the same periodic family (the halogens) and thus the number of valence electrons are the same