All you need to do is to look at both sides of the equation and see who has the same element, state, coefficient, and charge and those will be your spectator ions.
In this question, the spectator ions would be 
and 
.
1) solid
2) ductile
3) malleable
4) silver in color
Malleable means that it is "flexible" or can be permanently reshaped easily. Ductile means that it can be drawn out into a wire. Aluminum foil's state of matter is solid, and it appears in a silver color.
It doesn't transfer through Thermalizing
Carbon is the only possible solution in this question for the reason that the chemical formula for glucose is c6h12o6 (6, 12 and 6 underscore) and carbon dioxide is co2. Both of the chemical formula contains carbon that is why that is the main element.
Answer:
Below are some patterns in the charge for elements in each group.
Group 1 elements : 1 valence electron and form ions with charge +1
Group 2 elements : 2 valence electrons and form ions with charge + 2
Group 3 elements : 3 valence electrons and form ions with charge + 3(there are some exceptions as well)
Elements in groups 4 and 5 are unpredictable also the D block elements consist of multiple oxidation states..
Group 6 elements : 6 valence electrons, form ions with charge -2
Group 7 elements: 7 valence electrons, form ions with charge -1
The octet rule is being followed, the elements form either ionic bond or covalent bond to fulfill it.
eg: when a K atom forms a K+ ion, the ion has the same electron configuration as the noble gas Ar (argon).
When an O atom gains 2 electrons to form the O²⁻ ion, the ion has the same electron configuration as the noble gas Ne (neon).
Note: Boron (B) is in Group 3 but doesn't form ions.
