Answer : The answer is,
Explanation :
Scientific notation : It is defined as the way or representation of expressing the number that are too big or too small that is written in the decimal form. That means always written in the power of 10 form.
For example : 8000 is written as,
in this notation, the significant figure is, 1 but
in this notation, the significant figures are, 2
The given problem are :

According to the divide and multiplication rules of scientific figures, the final answer is only as precise as the value with the least number of significant figures.
Hence, the answer is,
Answer: Esta tendencia es tan regular que el poder de combinación, o valencia, de un elemento se definió una vez como el número de átomos de hidrógeno unidos al elemento en su hidruro. El hidrógeno es el único elemento que forma compuestos en los que los electrones de valencia están en la capa n = 1.
Explanation:
¡Espero que esto ayude!
Energy is stored in chemical bonds during photosynthesis.
During photosynthesis, the radiant energy from the sun is converted to chemical energy in carbohydrates.
Inorganic materials in the form of carbon dioxide and oxygen combine to form carbohydrates in the presence of radiant energy according to the equation below:

The energy is thus, stored in chemical bonds in the carbohydrate and this is what is oxidized during respiration to release the locked energy.
More on photosynthesis can be found here: brainly.com/question/1388366
Answer:
Ca
2+
<K + <Ar<Cl − <S 2−
Explanation:
Ar,K +
,Cl −
,S 2−
,Ca 2+
have the same number of electrons. Their radii would be different because of their different nuclear charges. The cation with the greater positive charge will have a smaller radius because of the greater attraction of the electrons to the nucleus. Anion with the greater negative charge will have the larger radius. In this case, the net repulsion of the electrons will outweigh the nuclear charge and the ion will expand in size. Hence the correct order will be Ca
2+ <K + <Ar<Cl − <S 2−
Because of the strong attractions between polar water molecules.