You seem to be missing a word there. I'm going to guess that you're looking for reactive. Metals that grow dull (or are oxidized) on contact with air are more reactive than metals that don't oxidize in air (or do so very slowly).
metals
Metals are typically shiny, malleable, and good conductors of electricity.
No. None of the Group 1 and Group 2 elements of the periodic table, the alkali and alkali earth metals respectively, stay shiny when exposed to air. They all react with moisture in air, and they tarnish quickly. A number of other metals will not stay shiny, either. Iron can be polished, but it will oxidize (rust) if left in air. Some metals will not react with air or the moisture in it, and some will. The results are mixed in that there are a lot of transition metals (Groups 3 through 12 on the periodic table), and each one would have to be evaluated independently (or with its "group mates") to discover if it would stay shiny. Links are provided to some relevant Wikipedia articles. The links are to the groups of metals, and each element in the Group chart is a hyperlink to that element. It should make it easy to do a quick search of the metals to get a complete answer, if that is what is desired.
They are in between the metals and non metals
Not all metals have lustre(that is, to be shiny) nor are all in solid form. It is just a characteristic property found among majority of the metals. For example, sodium is a metal which lacks lustre and mercury is in liquid form at room temperature.
Non-metals are not normally shiny.
There are quite a few metals that are shiny including gold. Silver and titanium are also metals that are shiny when polished.
They were exposed to and reacted with oxygen in the air.
metals are malleable in nature
Yes, gallium has a shiny appearance similar to shiny metals like aluminum. However, its shiny surface can tarnish quickly when exposed to air.
metals
Yes, it is.
Most non-metals do not have shiny appearances. They often have dull or non-reflective surfaces due to their lack of free electrons that can move around and reflect light. Some non-metals like iodine or graphite can appear shiny under certain conditions, but this is not common.
Alkali Earth metals are shiny. All metals have a property called luster witch means that they are shiny. All metals are also malleable, ductile, and are good conductors.
These are the alkali metals.
You can make almost anything shiny by polishing it.
Group 1 metals, such as lithium, sodium, and potassium, are shiny, soft metals with a silvery appearance. They are highly reactive and tend to tarnish quickly when exposed to air, forming a dull oxide layer on the surface. Group 1 metals are typically stored under oil to prevent them from reacting with moisture and oxygen in the air.