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>
My Apoligies for not being sooner.
Answer: The closer the particles get or the further apart they get, the greater the sound's amplitude. Sound amplitude causes a sound's loudness and intensity. The bigger the amplitude is, the louder and more intense the sound. - (This is copied)
General Answer : Its a change in sound, bassically the bigger the waves are, the louder the sound is.
Answer: See attached image
Explanation:
Answer:
Mass of 205 mL of the liquid is 164 g
Explanation:
We know, 
Here density of liquid is 0.798 g/mL and volume of liquid is 205 mL
So, mass of liquid = 
= 
= 164 g
hence mass of 205 mL of the liquid is 164 g.
The first one a neutral neutron strikes a large neutral nucleus