It is advised not to hold the thermometer by the bulb while reading it

yes is is true cuz when you hold the thermometer by a bulb the heat coming from the bulb will increase the thermometer

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

what is the question because that is not a question.