The answer is: K is more reactive than Ca because K has to lose only one electron to complete its outermost shell.
Potassium is a chemical element with atomic number 19 (number of electrons is 19).
Electron configuration of potassium is: ₁₉K 1s²2s²2p⁶3s²3p⁶4s¹.
Potassium is the alkali metal and has a single valence electron in the outer electron shell.
Periodic law is the arrangement of the elements in order of increasing atomic number.
For example all alkaline metals (I group of periodic table, Na, K, Cs...) loose one electron in chemical reaction and react vigorously with water.
Reactivity series is an empirical progression of a series of metals, arranged by their reactivity from highest to lowest (alkaline metals have highest reactivity and Noble metals lowest reactivity).
The ionization energy (Ei) is the minimum amount of energy required to remove the valence electron, when element lose electrons, oxidation number of element grows (oxidation process).
Alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons (one electron, earth alkaline metals (right next to alkaline metals) have higher ionization energy than alkaline metals, because they have two valence electrons.
In mineralogy and crystallography, a crystal structure<span>is a unique arrangement of atoms in a </span>crystal. Acrystal structure<span> is composed of a unit cell, a set of atoms arranged in a particular way; which is periodically repeated in three dimensions on a lattice.
Crystals create a harder more fitting structure so they tend to be a lot stronger than other compounds or elements</span>
The answer is D: Saturated.
A saturated solution is one in which the exact maximum amount of solute has been dissolved. So, new solute will not dissolve in the solution. In contrast, an unsaturated solution can hold more solute, so if that option were correct, the crystal would have dissolved.
The other two terms are a bit more complicated. A supersaturated solution is one holding an amount of solute above the sustainable limit. Because of that, when more solute is added, the solution will immediately adjust, and some solute will come out of solution in a precipitate. Because the crystal isn't growing, we can eliminate this option.
A concentrated solution is one holding a relatively large amount of solute. However, you can have concentrated solutions that are saturated and unconcentrated (the word for this is dilute) solutions that aren't saturated. Therefore, we can say that because the crystal doesn't dissolve, this solution is saturated, but we can't say with certainty that it is concentrated.
Because the first three options are invalid, as described above, while the scenario does describe a saturated solution, D is the correct answer.
1. Answer;
- Exothermic reaction
Explanation;
-Exothermic reactions are types of chemical reactions in which heat energy is released to the surroundings. Since enthalpy change is the difference between the energy of products an that of reactants. It means that in an exothermic reaction the energy of products is less than that of products. In this case an energy of 315kJ is released to the surroundings.
2. Answer;
Conserved
-The total amount of energy before and after a chemical reaction is the same. Thus, energy is conserved.
Explanation;
-According to the law of conservation of energy, energy is neither created nor destroyed. Energy may change form during a chemical reaction. For example, energy may change form from chemical energy to heat energy when gas burns in a furnace. However, the exact amount of energy remains after the reaction as before, which is true for all chemical reactions.
atomic mass=percentage of isotope a * mass of isotope a + percentage of isotope b * mass of isotope b+...+percentage of isotope n * mass of isotope n.
Data:
mass of isotope₁=267.8 u
percentage of isotope₁=90.3%
mass of isotope₂=270.9 u
percentage of isotope₂=9.7%
Therefore:
atomic mass=(0.903)(267.8 u)+(0.097)(270.9 u)=
=241.8234 u + 26.2773 u≈268.1 u
Answer: the mass atomic of this element would be 268.1 u
