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
2. answer is C.<span> Elements have the same physical and chemical properties in any period </span>
Answer:
Metalloids are metallic-looking brittle solids that are either semiconductors or exist in semiconducting forms, and have amphoteric or weakly acidic oxides. Typical nonmetals have a dull, coloured or colourless appearance; are brittle when solid; are poor conductors of heat and electricity; and have acidic oxides.
Explanation:
The best and most correct answer among the choices provided by your question is the second choice or letter B.
The iron cam is larger than the aluminum cam even if with the same size.
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Answer:
Alkaline earth metals
Explanation:
Group 2 has 2 valence electrons that they lose when being ionized, thus making their charge 2+.