What is a difference between an isotope and a ion

Photoelectrons with a maximum speed of 6.50 x 107 m/s are ejected from a surface in the presence of light with a frequency of 6.75 x 1014hz. if the mass of an electron is 9.10 x 10-31 kg, calculate in joules the maximum kinetic energy of a single electron. 3.84 x 10-15 j 1.92 x 10-15 j 5.92 x 10-23 j 3.07 x 10-16 j

Aball is thrown vertically upwards from the top of a tower with a speed of 100m/s.it strikes the pound near the base of the tower after 25sec . the height of the tower is

Which phrase describes the paleo-indians of prehistoric arkansas? a. grew cornb. lived in cliff dwellings c. crafted beautiful potteryd. hunted with stone-tipped spearswhich phrase describes native arkansas from the woodland traditiona. developed widespread agricultureb. hunted mastodon and woolly mammothc.built rectangle-shaped homesd. traded salt with other groups