Answer:
A. there is an isotope of lanthanum with an atomic mass of 138.9
Explanation:
By knowing the different atomic masses of both Lanthanum atoms, we can not tell anything about their occurence in nature. Therefore, all the last three options are incorrect. Because, the atomic mass does not tell anything about the availability or natural abundance of an element.
Now, the isotopes of an element are those elements, which have same number of electrons and protons as the original element, but different number of neutrons. Therefore, they have same atomic number but, different atomic weight or atomic masses.
Hence, by looking at an elements having same atomic number, but different atomic masses, we can identify them as isotopes.
Thus, the correct option is:
<u>A. there is an isotope of lanthanum with an atomic mass of 138.9.</u>
I dunno............................................
Maalox is the trade name for an antacid and antigas medication used for relief of heartburn, bloating, and acid indigestion in which
4 ml contains
= 320mg of aluminum hydroxide
= 320mg of magnesium hydroxide
= 32mg of simethicone
recommended doses = 4 times * 2 tea spoon = 8 tea spoon/ day
given = 1 tea spoon = 5 ml
8 tea spoon = 40 ml
hence,
amount of aluminum hydroxide = 320/4 * 40 = 3200mg = 3.2 g
amount of magnesium hydroxide = 320/4 * 40 = 3.2 g
amount of simethicone = 32/4 * 40 = 320 mg = 0.32g
To know more about antacid visit :
brainly.com/question/1328376
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360 seconds?
i’m guessing that is the answer as the question is unreasonable
