She I study I like to read the question while covering the answer and then answer it I. My head. Then I check to see if it is right. Also if you want flash cards just search up the topic with quizlet for online quizzes about your subject. If needed take 25 mins to study with 5 min breaks.
The average atomic mass is calculated by the expression:
Average atomic mass = Σzₓ(Aₓ)
where zₓ is the relative abundance of an isotope and Aₓ is the atomic mass of the isotope.
We calculate the mass of the isotope as follows:
10.81 = .1980 (10.012938) + .8020 (x)
x = 11.00 -----------> mass of the isotope
Answer:
B)
Explanation:
Dalton was the first scientist to propose an atomic model. He said that each element is composed of extremely small particles called atoms, which are indivisible, atoms of a given element are identical, and atoms of different elements have different properties.
With the advance of the studies, it was proven that elements are composed of small particles, atoms and that the atoms of each element are identical, and have different properties from atoms of different elements.
But, now we know that the atom can be divisible: it's formed by electrons, protons, and neutrons. So only postulate <em>ii</em> is no longer considered valid.
The answer to the question is a
