In the nucleus of an atom, there are 18 protons and 20 neutrons. what are the atomic number and mass number of this isotope

Player kicks a soccer ball from ground level and sends it flying at an angle of 30 degrees at a speed of 26 m/s. what is the horizontal velocity component of the ball to the nearest tenth of a m/s?

Edward tolman explained the results of his study by theorizing that the rats were learning about the maze during every trial but they a. were agitated because other groups were getting reinforcement b. could not remember how to demonstrate it without reinforcement c. were not motivated to demonstrate it without reinforcement d. seemed to be too lazy to actually work without reinforcement

Order the sequence of ideas that lead to marie curies discovery of radioactive elements number the events in chronological order starting with the oldest