The answer is d because it said so
The Earth is divided into three chemical layers: the Core [Inner Core (D) and Outer Core (C)], the Mantle (B) and the Crust (A). The Core is predominantly composed of iron and nickel. Even after 4.5 billion years of cooling, the Earth's core remains very hot.
Answer:
paired electrons is magnetic configuration
Answer: Region 3
Explanation: The temperature and time graph suggests that region 3 is the region in which the substance can co exist in both the phases that is solid phase and liquid phase.
Region 1 explains that the the solid has just started melting and there occurs a break point and then region 2 again explains that the solid is taking more time with temperature to get converted into the liquid and thus region 3 explains the equilibrium between the two phases.
This question comes with this list of answer choices:
<span>A. CO₂
B.N₂O
C.NaCl
</span><span>
D.C₆H₁₂O₆
</span>
Answer: option C.NaCl
Justification.
1) When two diferent elements join together chemically they can form either a covalent bond or a ionic bond.
2) When the bonds are covalents the compound is called covalent, when the bonds are ionics the compound is called ionic.
3) To predict whether the compound is ionic or covalent, you must see the electronegativities of the elements.
4) Ionic compounds require the formation of ions, a posititve ion and a negative ion. The positive ion is formed when the element loses one or more electrons. The negative ion is formed when the element gains one or more electrons.
Then, in the formation of a ionic compound it is implicit the exchange of electrons (one element gains the electrons that the other lose) and this is possible, when the difference in electronegativities are high enough.
5) So, you must look at the electronegativities to make your prediction. In the given options, the compounds of the options A, B and D are between non-metals. Then, you can predict that their electronegativities are not as much differet as to form ions. They will form covalent bonds.
6) Being sodium and chloride a metal and non-metal, you can expect that their electronegativities differ quite enough to form the ionic bond (this is not true for any pair of non-metal and metal elements, but being them the only pair of metal - non metal elements, this is the only option).
This leads to the conclusion that the NaCl formula shows an ionic compound, and is the answer.
