The elements of same group are placed in same group as they have similar properties. So Calcium is the element which resembles Mangesium.
Calcium and Magnesium both are alkaline earth metals.
They have similar properties as they have similar outer or valence shell electronic configuration
The general electronic configuration of alkaline earht metal is ns2
The electronic configuration of Mg [atomic number 12] and Ca [atomic number 20] are
![[Ne]3s^{2}](https://tex.z-dn.net/?f=%5BNe%5D3s%5E%7B2%7D)
and ![[Ar]4s^{2}](https://tex.z-dn.net/?f=%5BAr%5D4s%5E%7B2%7D)
respectively.
It has 92 protons, 92 electrons, and 238 — 92 : 146 neutrons.
The contribution to the nature of light-
Thomas Young - wave nature of light (double-slit experiment)
Max Planck - E = hv
Albert Einstein - a quantum theory of light
Thomas Young proposed the most important double-slit experiment which shows that light acts like a wave and shows the pattern of interferences.
Max Planck proposed that light is proportional to frequency. He gave the equation, E = hv, where E is the energy of light, h is Planck's constant, and v is the frequency.
Albert Einstein proposed the quantum theory of light. He determined that light exists in discrete quanta of energy called photons.
To learn more about the nature of light, visit: brainly.com/question/4423091
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Yes, when molten candle wax solidifies it is a chemical reaction
<u>Explanation:</u>
Basically Wax is crystalline so once the candle light melts it freezes taking back the solid state to the room temperature.
When the room temperature is below the freezing point, the liquid candle wax, turns into solid state again, therefore this process is called solidification. The process of freezing or solidification is a process when an object turns liquid and freezes back to solid state.
Indeed, Yes, when molten candle wax solidifies it is a chemical reaction
Answer: 
will have a greater partial charge.
Explanation:
A polar covalent bond is defined as the bond which is formed when there is a low difference of electronegativities between the atoms, thus resulting in charge difference. Example:
Non-polar covalent bond is defined as the bond which is formed when there is no difference of electronegativities between the atoms and thus there is no charge difference. Example: 
Ionic bond is formed when there is complete transfer of electron from a highly electropositive metal to a highly electronegative non metal. The electronegative difference between the elements is high. The charges on cation and anion neutralise each other. Example: 
Thus as will have greater partial charge.
