Okay Elements can combine to created element compounds a few examples can be lets say Gold(Au) Is an example of an Iconic Compound (usually a common compound). An Element Mixture is literal a mixture Ex. Brass. Brass is usually 10% copper and 45% zinc. So in order to get Brass you must physically m<span />ix copper with zinc and the other metal (sorry i don't remember the name) Also mixtures tend to not be chemically constant, this is because it was physically mixed rather than all of the atoms be the same if they were chemically combined.
Explanation:
Noble gas configuration is defined as the configuration which contains completely filled orbitals.
For example, oxygen atom when gain two electrons then it forms oxygen ion (
).
Atomic number of oxygen atom is 8 and so, its number of electrons will also be 8. But when it gain two electrons then it has total 10 electrons. Hence, electronic configuration of
is as follows.

Since, there are completely filled orbitals in an
ions. Therefore, it means this ion has a noble-gas configuration.
Thus, we can conclude that any specie which shows completely filled orbitals will have noble-gas configuration.
What are the options the your question
Answer:
B.) Adhesion
Explanation:
A.) is incorrect. Viscosity is a measure of internal friction that affects the fluidity of a liquid.
B.) is correct. Adhesion is the ability of water to stick to other substances (which are not water).
C.) is incorrect. Surface tension is the tension created by the bonds of the surface particles.
D.) is incorrect. Density is a ratio that compares mass to volume.
Answer : The correct option is, forms of the same element that differ in the number of neutrons in each atom
Explanation :
Isotopes : It is defined as the forms of same element that have the same number of protons and electrons but differ in the number of neutrons.
For example : Carbon-12, carbon-13 and carbon-14 is an isotopes due to the same number of protons and electrons and different number of neutrons.
Carbon-12
Atomic number = 6
Atomic mass = 12
Atomic number = Number of protons = Number of electrons = 6
Number of neutrons = Atomic mass - Atomic number = 12 - 6 = 6
Carbon-13
Atomic number = 6
Atomic mass = 13
Atomic number = Number of protons = Number of electrons = 6
Number of neutrons = Atomic mass - Atomic number = 13 - 6 = 7
Carbon-14
Atomic number = 6
Atomic mass = 14
Atomic number = Number of protons = Number of electrons = 6
Number of neutrons = Atomic mass - Atomic number = 14 - 6 = 8