Chapter 3: Basic Review. Flashcards
Scientific models are like architects’ models; they are ___________ representations of something rea.
simplified but useful
According to the model presented in this chapter all matter is composed of tiny _________.
Particles
According to the model presented in this chapter, the amount of motion of particles is proportional to __________.
Motion
Solids, gases, and liquids differ in the freedom of motion in their particles and in how strongly the particles _______ each other.
attract
An increase in temperature usually causes a solid to ________ somewhat.
vaporize
Particles in a liquid are still close together, but there is generally more ______ between them than in a solid. Thus, when a solid substance melts to form a liquid, it usually _____ to fill a slightly larger volume.
empty space + expands
The freedom of movement of particles in a liquid allows liquids to _________, taking on the shape of their container.
flow
When a liquid’s temperature is higher, its particles are moving faster and are therefore more likely to ________ from the liquid
escape
The average distance between particles in a gas is about __________ the diameter of each particle. This leads gas particles to take up only about __________ of the total volume. The other __________ of the total volume is empty space.
0.1%, 99.9%, 70%
According to our model, each particle in a gas moves freely in a __________ until it collides with another gas particle or with the particles of a liquid or solid.
straight line path
A liquid has a constant volume, but the__________ movement of the gas particles allows gasses to expand to fill a container of any shape or volume.
busy
Elements are substances that cannot be chemically converted into _________ ones.
simpler
By the year 2014, ______ elements had been discovered, but ______ of these elements are not found naturally on earth, and chemists don’t generally work with them.
118; 28
The periodic table is arranged in such a way that elements in the same _______ have similar characteristics.
vertical column
Metals are malleable, which means they are capable of being ______ by blows of a hammer.
extended/shaped
At room temperature and normal pressures, most of the elements are ________, two of them are _____, and eleven are ______.
solid, liquid, and gas.
For our purposes, we can think of the atom as a sphere with a diameter of about __________ meter.
10^-10
A 1/2-carat diamond contains about 5 x 10^21 atoms of carbon. If these atoms were arranged in a straight line with each one touching its neighbors, the line would stretch from here to the ______.
sun
We know that objects of opposite charge attract each other and that objects of the same charge _____ each other.
repels
The diameter of a typical nucleus is about _______ meter.
10^-15
Nearly all the mass of the atom and al of its positive charge are found in a nucleus about _______ the diameter of the atom itself.
10^-10
Chemists use a model for electrons in which each electron is visualized as generating a ______- of negative charge that surrounds the nucleus.
cloud
When an atom _______ one or more electrons, it then has more electrons than protons and more minus charge than plus charge. Thus it becomes an anion, which is negatively charged.
loses
Although all of the atoms of a specific element have the same number of ________________, they do not necessarily all have the same number of ____________.
protons, neutrons
Atoms are assigned to elements on the basis of their _________ characteristics
chemical
When an atom _______ one or more electrons, it then has more protons than electrons and more plus charge than minus charge. Thus it becomes a cation, which is positively charged.
gains
Because it displays the ________________, the periodic table can be used to determine the number of protons and electrons in an uncharged atom of any element.
atomic number
Each noble gas particle consists of a _______.
single atom
Hydrogen gas is very similar to helium gas, except that each of the particles is a hydrogen ________.
atom
Because of the size and number of carbon atoms in any normal sample of carbon, it is ______________ to count the atoms directly
impossible
The unit most often used to describe the mass of atoms is the atomic mass unit, whose symbol is u or amu. An atomic mass unit is defined exactly ____________ the mass of an atom of carbon-12.
half
The atomic mass of any element is the _______ average of the masses of the ________ occurring isotopes of the element.
weighed ; naturally
A mole is an amount of substance that contains the same number of particles there are in 12 g of carbon-12.
6.022 x 10^23
The number of grams in the molar mass of an element is the same as the element’s
atomic mass
