An unknown element has two stable isotopes. 92.41 percent of all atoms of this element have a mass number of 7. The remaining 7.59 percent of atoms of this element have a mass number of 6. Which of the following is MOST LIKELY to be true about the average atomic mass
of the unknown element
The average atomic mass is slightly lower than 7 but much higher than 6.
The average atomic mass is 6.5
There is no way to estimate the average atomic mass without knowing the identity of the element.

Which position represents spring in the southern hemisphere? a) b) c) d)

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.