Science Homework Help

25. From left to right across a period in the periodic table, elements become less _________metallic __ and more

___non metallic___________ in their properties.

26. Francium has 36 isotopes, but only francium-223 occurs in nature. Francium-223 spontaneously emits particles and energy, so francium-223 is a(an) _____________ of francium.

27. At sea level, water ______________ at 100°C.

28. Cooking requires continuous addition of energy to the chemical reactions that are taking place. The chemical reactions involved in cooking can be described as __________________.

29. The ________________ theory of matter states that all particles of matter are in constant motion.

30. In Rutherford’s experiments, some of the _______________ aimed at gold atoms bounced back, suggesting that a solid mass was at the center of the atom.