True or false 11. The gravity of a black dwarf is so great that
nothing can escape.
12. The main features of the universe are galaxies.
13. The most common element in most stars is
helium
14. Sunspots are dark, cooler areas on the surface
of the Sun.
15. The brightness of most stars increases as the
star's surface temperature decreases.
16. The Sun and all the planets in the solar system
are in the Milky Way Galaxy
17. Each element gives off its own spectrum of
light
18. To separate white light into the colors of the
rainbow, scientists can use a prism.
19. Galaxies with no regular shape are called
elliptical galaxies.
20. Streams of gas shooting from the Sun's
surface are called prominences.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).