Which of the following observations indicates that an atom has neutrons?
a. some uncharged particles are scattered by a beryllium atom when it hits a gold foil.
b. some uncharged particles bounce back from a gold foil when it is bombarded with alpha particles.
c. a radiation with neutral particles is emitted when alpha particles strike beryllium atoms.
d. a radiation which attracts electrons is produced when a beryllium atom is bombarded with alpha particles.
first row:number of protons: 20; number of neutrons: 20; atomic number: 20; mass number: 40; element: calcium; symbol: ca.
second row:number of protons: 9; number of neutrons: 10; atomic number: 9; mass number: 19; element: fluorine; symbol: f; explanation
the atomic number of an atom is the same as its number of protons. there are 20 protons in the atom in the first row. its atomic number will be 20.
the mass number of an atom is the sum of its number of protons and its number of neutrons.there are 20 protons and 20 neutrons in the atom in the first row. what will be its mass number? the mass number of the atom in the second row is 19, meaning that there are 19 protons and neutrons in total in that atom. on top of that, the number of protons in that atom is 9. what will be the number of neutrons in that atom?
elements on an periodic table are arranged by their atomic number. what's the symbol of the element with atomic number 20? what's the symbol of the element with atomic number 9? the element with atomic number nine is fluorine. the symbol for fluorine is "f", which happens to be the label for that blank.
i dont know but i think its because of chemical changes
i would say c. petroleum
a is wrong
b is impractical for "mainly used"
d thats too expensive
a. some uncharged pa...