Which list of elements is arranged in order of increasing electronegativity?
a. be, mg, ca
b. f, cl, br
c. k, ca, sc
d. li, na, k

Option (c) is the correct answer.

Explanation:

Electronegativity is defined as the ability of an atom or element to attract the electrons from another atom towards itself.

Non-metals are the species which are electronegative in nature. Whereas metals are the species which are electropositive in nature.

For example, F, l, Br and I are group 17 elements. These are electronegative in nature but their electronegativity decreases from fluorine to I.

Whereas Li, Na, K are alkali metals and most electropositive in nature.

Similarly, Be, Mg, Ca are group 2 elements and they are also electropositive in nature. When we move from top to bottom in a group then there is a decrease in electronegativity of the non-elements.

But when we move from left to right in a period then due to decrease in size of the atoms there will be increase in electronegativity of the atoms.

Thus, we can conclude that K, Ca, Sc list of elements is arranged in order of increasing electronegativity.

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3

the answer is c. nacl