Can you see Mercury with the naked eye?
Yes, Mercury is one of the five planets (excluding Earth) that you can see relatively easily with the naked eye. It's the most difficult of those five planets but it is certainly possible to see without a telescope.
Because Mercury is close to the Sun, from our viewpoint it always appears in the same area of the sky as the Sun. If the Sun is above the horizon you won't be able to see Mercury because the Sun's light overwhelms it. Instead you have to wait until such time as the Sun is below the horizon and Mercury is above it. This means that Mercury is visible for some time after sunset or before sunrise. You will never see mercury in the Middle of the night.
By far the easiest way to know where and when to find Mercury is to use a stargazing app.
Mercury varies a lot in its brightness. Sometimes it's barely bright enough to see but at its brightest it looks like an average star and it can even be brighter than some of the other planets.
Important safety tip: If you're using a telescope or binoculars to look at Mercury, wait until the Sun has completely set (in the evening) or stop before the Sun rises (in the morning). If you accidentally look at the Sun through a telescope you can seriously damage your eyes.
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