Answer:
3) Warm Temperatures and High pressures
Explanation:
This is the typical characteristic of southern air masses moving north
A solid to a liquid, the boiling of water, solid the water molecules vibrate condensed but as a liquid they are still isolated in a controlled area and also reflect off one another more, liquid to a gas they do not and move freely until condensation occurs
Answer: 66
Explanation: To find the mass number you would have to add the number of protons and the number of neutrons.
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>
