I believe you have to label out the positive metal ion and the delocalized electrons. They're the 2 things that makes up a metal structure.
In the diagram, the circles with the + symbol are the positive metal ions, since + represents positive. And the remaining - circles are the delocalized electrons, as electrons are negative.
And for how a metal conducts electricity, since they're delocalized mobile electrons present in any metal structures, they're able to move away from the metal to the positive side of the battery and more electrons can replace their place flowing from the negative side.
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>
It is important to use low flame when evaporating water from a recovered filtrate because then the water and filtrate will not spatter and the filtrate can also be recovered after evaporating water.
If flame is not low then water as well as got spatter so it is important to use low flame so that the water and filtrate will not spatter.
The A horizon is a surface horizon that largely consists of minerals (sand<span>, </span>silt<span>, and </span>clay) and with appreciable amounts of organic matter. This horizon is predominantly the surface layer of many soils in grasslands and agricultural lands.<span>These </span>materials typically<span> accumulate through a process termed illuviation, wherein the </span>materials<span> gradually wash in from the overlying.</span>
