The size of ions as measured by ionic radii varies in a systematic manner. the size of the ion can be explained in part by effective nuclear charge, zeff, which is the net nuclear charge felt by an electron. the effective nuclear charge takes into account the actual nuclear charge and the shielding of this charge by inner electrons. when an atom loses electrons, the resulting cation is smaller both because the remaining electrons experience a larger zeff and because these electrons are usually in orbitals closer to the nucleus than the electrons that were lost. the more electrons that are lost, the smaller the ion becomepart arank the following ions in order of decreasing radius: rb+,k+,li+,cs+, and na+.rank from largest to smallest radius. to rank items as equivalent, overlap them. part brank the following items in order of decreasing radius: ca, ca2+, and ca2−.rank from largest to smallest radius. to rank items as equivalent, overlap them. part cthe following ions contain the same number of electrons. rank them in order of decreasing ionic radii. cl^- ; ca^2+ ; s^2- ; k+ ; p^3-; sc^3+rank from largest to smallest radius. to rank items as equivalent, overlap them.

1:Decreasing atomic radii

C's+,Rb+,K+,Na+,andLi+

2:decreasing atomic radii

C2-,Ca&C2+

3:from largest

Sc3+,Cl-,S2-,P3-,K+&Ca2+

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.