Chapter 3 Book Notes

What are the building blocks of matter • each type

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Unformatted text preview: What are the building blocks of matter? • Each type of atom corresponds to a different chemical element • Atoms are made of particles that we call protons, neutrons, and electrons • Protons and neutrons are found in the tiny nucleus at the center of the atom • Rest of atom’s volume contains electrons, which surround the nucleus • The properties of an atom depend mainly on the amount of electrical charge in its nucleus; an object’s electrical charge is a measure of how strongly it will interact with other charged particles • An atoms is held together by the attraction between the positively charged protons in the nucleus and the negatively charged electrons that surround the nucleus • Atoms often lose or gain electrons, in which case they obtain a net electrical charge called an ion • A positive ion is an atom that has lost one or more electrons so that it has more positive than negative charge overall • A negative ion is an atom that has gained one or more electrons, giving it a net negative charge • Atomic number is number of protons in the nucleus • Combined number of protons and neutrons in an atom is called atomic mass number • Versions of an element with different numbers of neutrons are called isotopes of the element • Atoms can combine to form molecules • Substances composed of molecules with two or more different types of atoms are called compounds • Life on Earth is based on the complex chemistry of molecules (compounds) containing carbon, which are called organic molecules (or organic compounds) • Three phases: solid, liquid, gas • Chemical bond – the name we give to the interactions between electrons that hold the atoms in a molecule together • Phase changes occur when one type of bond is broken and replaced by another • Changes in either pressure or temperature can cause phase changes • The melting point is the temperature at which the water molecules finally break the solid bonds of ice • Boiling point – all bonds between adjacent molecules are broken so that the water can exist only as a gas • The process by which molecules escape from a solid is called sublimation, and the process by which molecules escape from a liquid is called evaporation • Conclusion: Pressure has an important effect because high pressure can cause a substance to remain in the solid phase even when the temperature is above the low- press boiling point. What is energy? • Energy is what makes matter move • Kinetic energy – energy of motion • Radiative energy – energy carried by light • Potential energy – stored energy • Conclusion: Although some form of stored energy is available almost everywhere, in most cases there is no viable way for life to extract the energy for its own use....
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What are the building blocks of matter • Each type of...

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