Helium,it has an atomic mass of 4,which means total no. of protons and neutrons,so I think you meant 2 protons and an atomic mass of 4
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>
Answer:
your answer to your question is B
Answer:
3Ca₍s₎ + 2FeCl₃ -------------------------------------------------------------> 3CaCl₂ + 2Fe₍s₎.
Explanation:
Iron(III) chloride is also known as Iron trichloride and it has the molar mass value of 162.2 g/mol and density of 2.9 g/cm³.
<em>The balanced equation for the chemical reaction between solid calcium and iron (III) chloride is given below as: </em>
<em />
3Ca₍s₎ + 2FeCl₃ -------------------------------------------------------------> 3CaCl₂ + 2Fe₍s₎.
This kind of chemical reaction is known as <em>single displacement reaction or single replacement reaction. </em>
<span> Ethyl Mercaptan
Hope this helped!</span>
