Which sequence of atomic numbers represents elements that have similar chemical properties? 3, 12, 2, 40
4, 20, 38, 88
19, 23, 30, 36
9, 16, 33, 50

Why does the sun appear to be the brightest star in the sky? a- its apparent brightness is much greater than other stars. b- it burns more gas, making it brighter than any other star. c- it is the largest star in the galaxy, so it is the brightest star. d- its relative distance to earth is closer than the other stars.

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy

Explain how global warming could have affected yellowstone frog and salamander habitat's, resulting in changes in the populations of these species