chapter 17
how many different elements are there
15 elements
how many electrons can the innermost shell of an atom have?
2 electrons
how many different elements are in a water molecule?
2 hydrogen, one oxygen
what kind of charge is on an atom that has fewer electrons than protons?
a net charge (positive)
when a nuclear is electrically natural, what is it called?
a neutron
to see a molecule you should use what kind of microscope?
an electron microscope
there are about as many atoms of air in our lungs at any moment as there are breathes if air in __________
atmosphere
protons, neutrons, and electrons combine to form what?
atoms
why are isotopes
atoms of the same elements having different number of neutrons
why can we sat that a granite block is mostly empty space?
bc its made up of atoms which are mostly empty space
how does the periodic table arrange the elements
by atomic number and electron arrangements
what do you get if you remove two protons from an oxygen nucleus
carbon
elements that are above or below each other in the periodic table have one more or one less
electron shell
in an electrically natural atom, the number of protons in the nucleus is balanced by an equal number of what other particle?
electrons
what particles do not exist in the nucleus
electrons
there are slightly more than 100 known atoms that combine to form all living and nonliving matter that we know about. what are these atoms called?
elements
assuming all the atoms exhaled by Julius Ceasr in his last dying breath are still in the atmosphere, about how often do you breathe one of those atoms?
every time you inhale
of the elements hydrogen, iron, lead and uranium, which has the most massive atom?
hydrogen
which element makes up over 90 percent of the known atoms in the universe?
hydrogen
what do you get if you add one neutron to a hydrogen nucleus?
hydrogen isotope
nuclei of atoms that make up a newborn baby were originally made where?
in ancient stats
nearly all the elements heavier than hydrogen that occur today were created where?
in the deeper interior of stars
where is most of the mass of an atom located? does this part of the atom also account for most of the atoms volume?
in the nucleus. no it doesn't since its less massive then trillionth of the volume
how many different molecules are there
infinte molecules
sometimes an atom has more or fewer electrons than it does protons. what is the name of such an atom?
isotope
which is the largest , a molecule atom proton or nuclus
molecule
atoms and molecules are in a state of constant agitation called what
molecules
atoms combine together to form what
molecules
is air a compound? why or why not
no bc age proponents of an atom vary
if we doubled the magnifying power of the most powerful optical microscope in the world would we be able to see atoms? why or why not
no bc the atoms are smaller than the wave lengths of visible light
at the center of every atom is a mass filled region. what is this region called?
nucleus
most of the matter if the universe is in which phase ?
plasma
what are the kinds of electric charge
positive, negative and natural
elements that are side by side in the periodic table have one more or one less
proton
which is the smaller, a molecule atom proton or nuclus
proton
what articles can be nucleons?
protons and neutrons
what determines how atoms combine to form molecules?
the arrangement of electrons
solid matter is mostly empty space. why don't solids fall through one another?
the molecules vibrate about fixed positions
what makes an element distinct
the number of protons
what defines the atomic number
the number of protons in the nucleus on an atom
what is brownian motion?
the perpetual jiggling of particles that are just large enough to be seen
are compounds always made of molecules?
they aren't always made of molecules
of the elements hydrogen, iron, lead and uranium, which has the most least massive atom?
uranium
