Answer:
C. 100.7 amu
Explanation:
Isotopes of an element are atoms of an element with the same atomic number but different atomic masses. Each atomic mass of an isotope is known as an isotopic mass. An element that exhibits isotope, that is, that have two or more isotopes has a relative atomic mass that is not a whole number.
Relative atomic mass of X is the sum of the products of the relative abundances of each isotope and its isotopic mass.
For Isotope ¹⁰⁰X: 30% × 100 = 30 amu
For Isotope ¹⁰¹X: 70% × 101 = 70.7 amu
Relative atomic mass of X = (30 + 70.7) amu = 100.7 amu
Therefore, the approximate atomic mass of X is 100.7 amu
Answer:
MM = 680g / mol
Explanation:
Hello! To calculate the molar mass of the compound (g / mol), I first have to calculate the molarity.
Molarity can be calculated from the osmotic pressure equation.
op = M * R * T
op = osmotic pressure = 28.1mmHg * (1 atm / 760mmHg) = 0.037atm
M = molarity
R = gas constant
T = temperature (K) = 20 ° C + 273.15 = 293.15K
M (mol / L) = op / R * T
M = 0.037atm / ((0.082 (atm * L) / (K * mol)) * 293.15K) = 0.0015mol / L
As I have the volume = 100ml * (1L / 1000ml) = 0.1L
I can calculate the amount of moles
n = M * V = 0.0015 * 0.1 = 0.00015mol
n = m / MM
m = mass
MM = molar mass
MM = m / n = 0.102g / 0.00015mol
MM = 680g / mol
It is mostly about an element, it usually goes like this: "which element has the bigger atomic size, Sodium or Oxygen? "
Answer:
The correct option is B
Explanation:
The number of valence electron(s) increases across the period and thus influences the direction of periodic trend of electronegativity, electron affinity and ionization energy across the period. Thus, making option B the answer.
It should be noted that option A is wrong because elements in the same period generally have the same number of electron shells and thus the distance of this shells from the nucleus remains the same throughout the same period and thus option C is also wrong. Option D is wrong because the periodic trends have to do with chemical reactions which actually involves electrons and not protons.
