Your answer would be (D), Noble Gases, or Inert Gases - The far right on the periodic table is also known as Group(0)., or Group 18 on the periodic table. Elements in this group includes, Neon(NE), Argon(AR), Krypton(KR), Xenon(XE), and Radon(RN).
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Answer:
D. It formed solely from atoms generated by the Big Bang.
Explanation:
From the history of the earth and it's solar system, options A to C are all correct ways of summarizing the Solar System's development. Because they have been proven to be in sync with reality of the solar system whereas the Bing bang theory has not done so as we know it says the universe was birthed from a huge explosion called big bang.
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
Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.
I'm pretty sure that significant figures is just the amount of numbers there is. So, in this case I think the answer would be D. 5