A model titled Model of H F shows a hydrogen atom with a positive charge bonded to a fluoride atom with a negative charge. What can you deduce based on the model?

The fluoride atom forms an ionic bond with the hydrogen atom.
The fluoride atom is more electronegative than the hydrogen atom.
The fluoride atom breaks its covalent bonds within the compound.
The fluoride atom bonded with hydrogen is a nonpolar compound.

In which situations is the principle of cross-cutting relationship useful in determining relative age?

1. emigration the movement of people from one place to another 2. immigration a situation in which resources are being used up at a faster rate than they can be replenished 3. migration the leaving of one's homeland to settle in a new place 4. overpopulation the movement of people to a new country 5. sustainable development a situation in which the birth rate is not sufficient to replace the existing population 6. underpopulation the ability to meet current needs without reducing the ability to meet future needs 7. unsustainable development the increase in the population of a city 8. urbanization a situation in which the number of people exceeds the available natural resources in an area

Match each symbol with its description.