Answer:
A
Explanation:
Crabs were exposed to a toxin in the water.
Answer:
A = 2
B = 1
Explanation:
The atomic number of lithium is 3.
Its atomic mass is 7 amu.
It is present in group group 1.
It has one valance electron.
Lithium is alkali metal it form salts.
It is silvery soft metal. It has lowest density as compared to all other metals.
It react vigorously with water.
It is used in rechargeable batteries which are used in camera, mobile, laptops etc.
The electronic configuration of Li:
Li₃ = 1s² 2s¹
Thus,
A = 2
B = 1
Answer: a rule that describes a pattern in nature.
Explanation:
Answer:
It's made of salt
Explanation:
The recipe has salt as an ingredient
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>
