Which of the following are formulations of the second law of thermodynamics?
A. It isn't possible to transfer heat from an object at a lower
temperature to another object at a higher temperature unless
work is done.
B. It isn't possible to change heat completely into work, with no
other change taking place.
C. Entropy of a system decreases over time.
D. All systems can convert energy from one form to another useful
form with 100% efficiency.

A and B.

Explanation:

Thermodynamic is the scientific study of heat energy. Its second law states that; the total entropy of an isolated system can never decrease over time, but it is constant if and only if all processes are reversible.

On thermodynamics, one of the German Physicists, Rudolf Clausius, formulated a statement that; heat energy would not suddenly flow from an object at lower temperature to another object at higher temperature.

Also, Lord Kelvin formulated a statement that; It is impossible to change all heat energy completely to work without losing energy.

Thus from these two formulations, options A and B are both correct.

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.