If we start with 10000 atoms of radium-226, how much would remain after 3,200 years?

What can be added to the examples section of each circle? endothermic: ice melting into water, and a heat pack becoming warm exothermic: a glow stick glowing, and fireworks exploding endothermic: ice melting into water, and an instant ice pack turning cold exothermic: fireworks exploding, and gasoline burning endothermic: a glow stick glowing, and a heat pack becoming warm exothermic: an instant ice pack turning cold, and ice melting into water endothermic: gasoline burning, and an instant ice pack turning cold exothermic: ice melting into water, and an instant ice pack turning cold

The wave shown on the electromagnetic spectrum disturb the medium it passes through a)different frequency. b)the same frequency .

The mass of a neutron is equal to the mass of a proton plus the mass of an electron. true or false false true