Chapter 3 - Atomic Structure Flashcards
What does an atom consist of?
Contains a small dense nucleus or core, which contains the bulk of the mass of the atom and carries positive electrical charges.
What is an electron?
An extremely small negatively charged particle.
What is a proton?
A small positively charged particle.
What is a neutron?
A small neutral particle.
What is the atomic number of an element?
The number of protons in the nucleus of an atoms of that element.
What is the mass number of an element?
The number of protons plus neutrons in the nucleus of an atom.
What is an isotope?
The atoms of one element that have different numbers of neutrons in their nuclei.
What is the relative abundance of an isotope?
The percentage of that isotope in the naturally occurring element.
What is radioactivity?
The spontaneous emission of radiation that occurs with certain isotopes and arises because some isotopes are unstable.
What is an Alpha ray/alpha particle?
Relatively heavy positively charged particles.
What is the penetration power for Alpha rays?
Low.
What are Beta rays/beta particles?
Beta rays are much lighter than alpha rays, they are negatively charged
What is the penetration power for Alpha rays?
Greater penetrating power than Alpha rays but less than that of Gamma rays.
What are Gamma rays?
Gamma rays are like X-rays and ultraviolet radiation. They carry no charge.
What is the penetration power of Gamma rays?
They are extremely penetrating.
Radioisotopes that emit alpha radiation…
Loose a helium nucleus, therefore making the substance loose 2 protons and two neutrons. The element goes down the periodic table by 2 (the bottom number) and looses 4 from the top number next to the element.
Radioisotopes that emit Beta radiation…
loose an electron, therefore moving the element up one on the period table and has no effect on the top number of protons + neutrons.
What is the half-life of a radioisotope?
The time required for half the atoms in a given sample to undergo radioactive decay. The half-life is independent of the initial amount of the isotope present.
What is the highest energy level called?
Valence electrons.
What is the outmost energy level called?
Valence shell.
What is an orbital?
The volume of space surrounding the nucleus of an atom through which one or two electrons my randomly move.
How many orbitals does the first energy level consist of?
One s orbital.
How many orbitals does the second energy level consist of?
Four orbitals, one s and three p orbitals.
How many orbitals does the third energy level have?
9 orbitals, one s, three p, and five d orbitals
