the element boron has two stable isotopes: boron-10 (10.0129 u) and boron-11 (11.0093 u). the periodic table reports a mass for boron as 10.811 u. what is the natural abundance of each boron isotope?

Which is a characteristic of mixtures?

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.