Consider the group 1a elements sodium (period 3), potassium (period 4), and rubidium (period 5). what would you predict about the ionization energies of these elements? na < k < rb na > k > rb c. rb < na < k d. na = k = rb

The correct answer is Na > K > Rb.  

The order predicted would be ionization energy of sodium is greater than the ionization energy of potassium, which is greater than the ionization energy of rubidium.  

The ionization energy refers to energy, which has to be supplemented to a gaseous atom in order to withdraw an electron and produce a positive ion. The ionization energy decreases in going down a group. The cause of the decline of the ionization energy down a group is that as one moves down a group, the size of the atom increases that signifies that the valence electrons get further away from the nucleus, and thus, less energy is required to withdraw the electrons.  

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l