If anyone this question i getting wrong answer. i don’t know why i keep getting wrong. could anyone me ? !

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?

How many neutrons does element x if it’s atomic number is 28 and its mass number is 87

Four point charges each having charge q are located at the corners of a square having sides of length a. find symbolic expressions for the following. (a) the total electric potential at the center of the square due to the four charges (use any variable or symbol stated above along with the following as necessary: ke.) vtotal= (b) the work required to bring a fifth charge p from infinity to the center of the square (use any variable or symbol stated above along with the following as necessary: w=