Remember that reduced means to gain electron, while oxidized means to lose electrons.

Using the equation: , for a spontaneous reaction to occur,  must be positive. With solid mercury as the product, any other solid can act as the reactants, and still give a positive , because it has the highest  value. 

As a result, the equation,, remains unchanged, and mercury ions will gain electrons and be reduced to liquid mercury. Any other paired equation must be inverted to give electrons.  

Remember: AN OX and RED CAT (the ANode is the site of OXidation, and REDuction takes place at the CAThode). Also remember OIL RIG (Oxidation Is Loss of electrons and Reduction Is Gain of electrons). The question asks us which species is produced at the cathode (site of reduction). Also, remember that electrons always flow from anode to cathode, and that galvanic cells are spontaneous reactions (positive ), and since electrons are negatively charged, they spontaneously flow from the anode (negative cell) to the cathode (positive cell) according to the law of attraction. Thus, we are looking for the species that gains electrons. Nickel goes from an oxidation state of  to .  is being produced because electrons are being transferred from the anode to the cathode. In this case, the nickel ions are gaining electrons to form  and this can only happen at the cathode.  

Using the equation: , for a spontaneous reaction to occur,  must be positive. With chlorine ions as the product, any other solid can act as the reactants, and still give a positive , because it has the highest  value. As a result, the equation,, remains unchanged, and chlorine gas will gain electrons and reduce to chlorine ions. Any other paired equation must be inverted to give electrons. 

Using the equation: , for a spontaneous reaction to occur,  must be positive. With solid lithium as the reactant, any other solid can act as the product, and still give a positive , because the  is the lowest value for lithium equation. Subtracting a negative number will give a positive value.

As a result, the equation,, will become inverted to make the solid lithium a reactant. . Solid lithium will give electrons, and oxidize, to reduce other ions. 

Remember: AN OX and RED CAT (the ANode is the site of OXidation, and REDuction takes place at the CAThode). Also remember OIL RIG (Oxidation Is Loss of electrons and Reduction Is Gain of electrons). The question asks us which species is produced at the cathode (site of reduction). Also, remember that electrons always flow from anode to cathode.

No knowledge about whether the cell is galvanic or electrolytic is needed, because the question assumes that the chemical reaction takes places.

 is being produced at the cathode because electrons transfer from the anode to the cathode. In this reaction,  are gaining electrons to form , and the gaining of electrons only happens at the cathode. Therefore,  is produced at the cathode. On the other hand,  loses electrons to produce  in the reaction, and the losing of the electrons only occur at the anode.

Remember: AN OX and RED CAT (the ANode is the site of OXidation, and REDuction takes place at the CAThode). Also remember OIL RIG (Oxidation Is Loss of electrons and Reduction Is Gain of electrons). The question asks us which species is produced at the anode (site of oxidation). Also, remember that electrons always flow from anode to cathode.

No knowledge about whether the cell is galvanic or electrolytic is needed, because the question assumes that the chemical reaction takes places.

 is being produced at the cathode because electrons transfer from the anode to the cathode. In this reaction,  are gaining electrons to form , and the gaining of electrons only happens at the cathode. Therefore,  is produced at the cathode. On the other hand,  loses electrons to produce  in the reaction, and the losing of the electrons only occur at the anode. Therefore,  is produced at the anode.

The atomic number is the number of protons present in the nucleus of an atom. This number does not change without changing the element. In elemental notation, the atomic number is found at the bottom left corner of the chemical symbol for the element. The upper number represents the nuclear mass of the atom, given by the sum of the protons and neutrons.

Elemental notation gives us insight into the particles that are found in a given atom. The atomic number in the lower left corner shows how many protons are in an atom, and the mass number in the upper left corner shows how many protons and neutrons are in an atom. As a result, we can find the number of neutrons in the ion in question by subtracting the atomic number from the mass number:

There are twenty neutrons in this potassium ion.

Let's start by identifying our starting atom. Cobalt has 27 protons. If the given atom has an atomic mass of 60, then it must have 33 neutrons.

An alpha decay is the emission of a helium nucleus with mass 4 (2 protons and 2 neutrons). This results in a daughter nuclide whose atomic number is 2 less and atomic mass is 4 less than the original element.

A beta decay is the conversion of a neutron to a proton, accompanied by the emission of an electron. This results in a daughter nuclide whose atomic number is 1 more than the original element, with no change to atomic mass. This process is done twice.

Doing 1 alpha and 2 beta decays gives a net change of -4 for the atomic mass and 0 for the atomic number.

To do this problem, all you have to remember is that the sum of the atomic numbers and atomic masses should be equal on the left and right sides.

Mass values: 

Atomic numbers: 

Look at your periodic table to find the identity of the resulting element.