The charge on an electron is indeed negative, and we typically represent it using the symbol "e" with a negative sign. However, when we write the magnitude of the charge of an electron, we often omit the negative sign for historical reasons and to avoid confusion.
The convention of omitting the negative sign when writing the magnitude of a charge is rooted in the way we express electrical quantities. In conventional electrical notation, positive charges are denoted without a sign, while negative charges are denoted with a minus sign. This convention simplifies mathematical expressions and makes them easier to interpret.
For example, if we have a system with one electron, the charge of the electron is -1e, where "e" represents the elementary charge. However, when we refer to the magnitude of the charge, we simply write "1e" instead of "-1e" to indicate the absolute value of the charge without the sign.
It's important to note that this convention is specific to electrical notation and doesn't imply that the negative sign is disregarded in the actual physical properties or behavior of electrons. The negative charge of an electron is a fundamental characteristic of the particle, and it is accounted for in all relevant equations and physical theories.