Answer:
"mole"
Explanation:
That is the definition of mole. Mole is a unit for the measurement of how much there is of something. In other words, in SI, 1 mol of a substance contains the same number of molecules/atoms as in 12 grams of carbon 12.
(Approximately 6.28 × 10^23 --> Avogadro's constant)
For further explanation, check out Wikipedia's article here:
https://en.m.wikipedia.org/wiki/Mole_(unit)
An isoelectronic series is where all of the ions listed have the same number of electrons in their atoms. When an atom has net charge of zero or neutral, it has equal number of protons and electrons. Hence, it means that the atomic number = no. of protons = no. of electrons. If these atoms become ions, they gain a net charge of + or -. Positive ions are cations. This means that they readily GIVE UP electrons, whereas negative ions (anions) readily ACCEPT electrons. So, to know which of these are isoelectronic, let's establish first the number of electron in a neutral atom from the periodic table:
Na=11; K=19; Rb=37; Cs = 55; Ca=20; S=16; Mg=12; Li=3; Be=4; B=5; C=6, Ar = 18
A. Na⁺: 11-1 = 10 electrons
K⁺: 19 - 1 = 18 electrons
Rb⁺: 37-1 = 36 electrons
B. K⁺: 19 - 1 = 18 electrons
Ca²⁺: 20 - 2 = 18 electrons
Ar: 18 electrons
S²⁻: 16 +2 = 18 electrons
C. Na⁺: 11-1 = 10 electrons
Mg²⁺: 12 - 2 = 10 electrons
S²⁻: 16 +2 = 18 electrons
D. Li=3 electrons
Be=4 electrons
B=5 electrons
C=6 electrons
The answer is letter B.
Answer:
0.170 M
Explanation:
M1V1=M2V2
(25.0mL)(0.123M)=(18.04mL)(x)
x= 0.170 M
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Answer:
The concentration of the resulting solution in parts per million is 177.97
Explanation:
Parts per million (ppm), is a unit of measure for concentration that refers to the number of units of the substance per million units of the set.
The concentration in parts per million expressed in mass / mass is calculated by dividing the mass of the solute (ms) by the mass of the solution (md, sum of the mass of the solute and the mass of the solvent), both expressed in the same unit and multiplied by 10⁶ (1 million).
So, being:
- md: 0.089 grams of KI + 500 grams of H₂O= 500.089 grams
Replacing:
ppm= 177.97
<u><em>The concentration of the resulting solution in parts per million is 177.97</em></u>
Answer:
An atom of Bromine (Br) forms an ion and becomes Br⁻
Explanation:
- Atoms of elements gain or lose electron(s) to attain a stable configuration and form ions.
- When an atom gains electron(s) it forms a negatively charged ion called an anion.
- For example, Bromine is a halogen and its atom requires to gain one electron to attain stability and form a bromine ion (Br⁻).
- When an atom loses electron(s) it forms a positively charged ion called a cation.
- For instance, atoms of calcium(Ca) requires to lose two electrons to attain stability and form calcium ion (Ca²⁺).
