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Ch 3 Physics

Structure of Matter

QuestionAnswer
What is an atom? the smallest particle of matter that has all the properties of an element
What particles are smaller than the atom? subatomic particles
What are the fundamental particles of an atom? electron, proton, neutron
What does the atom consist of? empty space
What determines the chemical element? the number of protons
What is the atomic mass number of an electron? zero
What are the particles in the nucleus called? nucleons
What are the two types of nucleons contained in the nucleus? protons and neutrons
What does the shell arrangement tell us about an atom? how it reacts chemically; how it combines with other atoms to form molecules
What do the shells represent? different electron binding energies or energy levels
The closer an electron is to the nucleus... the greater its binding energy
What is the normal state of an atom? electrically neutral, charge is zero
What is ionization? the removal of an orbital electron from an atom
If an atom has an extra electron or has had an electon removed, it is said to be what? ionized
The maximum number of electrons that can exist in each shell increases with what? the distance of the shell from the nucleus
How can the electron limit per shell be calculated? octet rule, 2n²
What does the "n" stand for in the octet rule formula? principal quantum number or shell number
What is the most electrons contained in the outer most shell? eight
What is the most electrons contained in the inner most shell? two
How many electron shells are there? seven
What is the first shell referred to as? K
What is the last shell referred to as? Q
What is the number of electrons in the outermost shell of an atom equal to? it's group in the periodic table
What does the number of electrons in the outermost shell determine? the valence of an atom
What is the number of electrons in the outermost shell of an atom equal to? its period in the periodic table
What is the force that keeps an electron in orbit? centripetal, the inward pull
The strength of attachment of an electron to the nucleus is referred to as what? electron binding energy
The more closer an electron is to the nucleus,and the greater the total number of electrons in an atom, the... more tightly it is bound
Which shell has the highest binding energy? K-shell
How do two atoms that are attracted to each other result in an ionic bond? they have opposite electrostatic charges
What is the emission of particles and energy in order to become stable refer to? radioactivity
The time required for a quantity of radioactivity to be reduced to one-half its orginal value refers to what? half-life
What is electricity? the flow of electrons
What is electrical energy? work that can be done when an electron moves through an electric potential difference (voltage)
What what is used to convert electric energy into thermal energy? kinetic energy of molecules and is closely related to temperature (heat)
What is used to convert electrical energy into mechanical energy? a motor by passing a coil or loop of wire through a magnetic field
What is used to convert mechanical energy into electric energy? a generator is used to convert mechanical energy to electrical energy
What is centrifugal force? the outward push or flying out from the center force so electrons maintain their distance from the nucleus while traveling in a circular or elliptical path
The further electrons are from the nucleus the lower their electron binding energy but they possess what? higher kinetic energy
The number of protons plus the number of neutrons in the nucleaus of an atom is called: atomic mass number, symbolized by "A", always a whole number
In the neutral atom, the number of electrons is equal to the number of protons. What is the number of protons called? atomic number, represented by "Z"
Atoms that have the same atomic number but different atomic mass numbers are: isotopes
Atoms of various elements may combine to form what kind of structures? molecules
Atoms that have the same atomic number and the same atomic mass number are referred to as: isomers
Any quantity of one type of molecule is a chemical: compound
Hydrogen, carbon, and nitrogen compose what percentage of the human body? 95 (over)
Water molecules make up what percentage of the human body? 80 (approximately)
What is the chemical union, between atoms, that is formed by sharing one or more pairs of electrons? covalent bond
What is the bonding that occurs because of an electrostatic force (attraction of opposite charges) between ions? ionic bond
To reach stability, the nucleus spontaneously emits particles and energy and transforms itself into another atom. What is this process called? radioactive disintegration
Any nucleus that emits radiation is referred to as: radionuclides
The emission of particles and energy in order to become stable is referred to as: radioactivity
Radioactive decay results in the emission of what? alpha particles, beta particles, and usually gamma rays
What are the two classifications of ionizing radiation? particulate, electromagnetic
What types of radiation are used in diagnostic ultrasound and magnetic resonance imaging? nonionizing
What are the two main types of particulate radiation? alpha particles, beta particles
What are the two forms of electromagnetic ionizing radiation of radiologic interest? x-rays, gamma rays
A helium nucleus that contains two protons and two neutrons. alpha particle
An electron emitted from the nucleus of a radionactive atom. beta particle
What type of radiation is most important in nuclear medicine? beta and gamma
What type of radiation is most important in radiography? only x-rays
What is the difference between x-rays and gamma rays? their origin
What type of radiation is emitted from the nucleus of radioisotopes? gamma rays; usually associated with alpha or beta emission
What type of radiation is produced outside the nucleus in the electron shells? x-rays
X-rays and gamma rays are often referred to as what? photons; they have no mass/charge; they travel at the speed of light, constant; have unlimited range in matter
Photon radiation loses intensity with distance but theoretically never does what? reaches zero
Created by: sunshineb