Does mass<span> alone provide no information about the amount or size of a measured quantity? No, we need combine </span>mass<span> and </span>volume<span> into "one equation" to </span>determine<span> "</span>density<span>" provides more ... </span>g/mL<span>. An </span>object has<span> a mass of </span>75 grams<span> and a volume of </span>25 cc<span>. ... A </span>certain object weighs 1.25 kg<span> and </span>has<span> a </span>density of<span> </span>5.00 g/<span>mL</span>
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>
Among the elements Barium has the lowest Ionization Energy.
<h3>What is Ionization Process ?</h3>
The process by which any neutral atom gets converted into electrically charged by gaining or losing electron is called Ionization Process.
K is an alkali metal it has to lose one electron to attain stable electronic configuration of an inert gas
For removing second electron , a stable configuration has to be broken and so will require high amount of energy.
Ca and Ba are alkaline earth metals.
They both have to lose 2 electrons to attain stable electronic configuration of noble gas.
They have low Iow Ionization Energy as compared to K.
Ca has higher Ionization Energy as compared to Ba because when we move down the periodic table , The ionization energy decreases.
Hence , Among the elements Barium has the lowest Ionization Energy.
To know more about Ionization Process
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There are 5 significant figures in the following number. All of the numbers essentially are significant.
