The highly reactive elements in group 7a are known for forming salts. what are they called? a. transition metals b. metalloids c. halogens d. noble gases

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

How are the terms group and period used on the periodic table

Which number should be placed before f2 on the reactants side equation to make equation balanced? xe + > xef4