Chemistry Questions

A metalloid is an element with properties between metals and non metals or the mix of both.

The six metalloids are arsenic, silicon, germanium, boron, antimony and tellurium.

Hence, silicon is the only metalloid in the given list.

Here I give you the first 30 Atomic elements names and their Atomic masses.

Atomic number      Element        Atomic mass
                             

        1                 Hydrogen           1

        2                  Helium              4

        3                 Lithium              6.94

        4                Beryllium            9.01

        5                  Boron               10.81

        6                Carbon               12.01

        7                Nitrogen             14.01

        8                Oxygen              15.99

        9                Fluorine              19.00

       10                Neon                 20.18

       11               Sodium               22.99

       12             Magnesium           25.31

       13             Aluminium            26.98

       14               Silicon                28.09

       15             Phosphorus           30.97

       16               Sulphur               32.07

       17               Chlorine              35.45

       18                Argon                 39.95

       19             Potassium              39.10

       20              Calcium                40.08

       21             Scandium              44.96

       22             Titanium               47.87

       23            Vanadium              50.94

       24             Chromium            24. 52

       25            Manganese            54.94

       26                Iron                  55.85

       27              Cobalt                 58.93

       28               Nickel                 58.69

       29              Copper                 63.55

       30                Zinc                   65.41

True, Water is a Pure substance and not a mixture.

We know that, A mixture is when two or more substances combine physically together. You can find that the mixture retains the properties of the original components.

In water, two hydrogen atoms combine with one oxygen atom chemically, forming a new substance that has properties different from hydrogen alone or oxygen alone.

Therefore, water is not a mixture; it is a compound and it is pure.

The Law of Definite Proportion states that the same compound, wherever found or however made, always contains the same elements combined together in the same fixede ratio by weight.

We know that polar substances are soluble in polar solvents and non polar substances are soluble in non-polar solvents only. Here the hydrocarbons are non-polar molecular substances and water is a polar solvent. So water can't dissolve hydrocabons.

Hence, as hydrocarbons are non-polar substances, they are insoluble in water as it is a highly polar solvent. 

Electronegativity is the tendency for an atom to attract electrons. There are general trends on the periodic table which you can use to determine the relative electronegativity for different elements, but otherwise you can also look at their valence shell and effective nuclear charge to determine their relative electronegativity.

Here from the given options, Lithium has least tendency to attract electrons and thus has a lower electronegativity.