Which statement describes how electric charges affect each other?
1. positive and negative charges repel
2. two positive charges attract
3. two negative charges attract
4. positive and negative charges attract

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?

What element has similar physical and chemical properties as boron.

Which subshell is represented by the actinides family?