Chapter 3 Flashcards
three types of subatomic particles
electrons
protons
neutrons
electron
subatomic particle that possesses a negative (-) electrical charge
- smallest, in terms of mass
- determine the chemical properties of an atom
proton
subatomic particle that possesses a positive + electrical charge
- carry the same amount of charge as electrons
neutrons
a subatomic particle that has no charge associated with it
- neutral
- same mass as protons
- 2000 times heavier than electrons
nucleus
- where all protons and all neutrons are located
- very small, dense, positively charged center of an atom
nucleus is always positively charged why?
because it contains positively charged protons
- it houses positive protons and neutral neutrons
- almost over 99.9% of the mass of an is concentrated where?
nucleus
small size of nucleus coupled with large amount of an atom causes?
materials to be extremely dense
nucleon
any subatomic particle found in the nucleus of an atom
- protons and neutrons both nucleon
what determines the volume or size of the atom
the motion of the electrons in the extranuclear region determines the volume
electron cloud
the volume occupied by the electrons
atomic number
the number of protons in it nucleus
Z atomic number = number of protons = number of electrons = Z
mass number
the sum of the numbers of protons and neutrons in its nucleus
- gives number of subatomic particles present in nucleus
mass number = number of protons + number of neutrons = A
calculating number of subatomic particles
number of protons = atomic number = Z
number of electrons = atomic number = Z
number of neutrons = mass number = A-Z
element
a pure substance in which all atoms present have the same atomic number
isotopes
atoms of an element that have the same number of protons and electrons but different number of neutrons
- always have same atomic number and different mass number
most elements found in nature exists in what form
isotopic form
characteristics of isotopes of an element
- have same chemical properties, but their physical properties are often slightly different
why does isotopes have the same chemical properties and different physical properties
- have the same number of electrons (chemical)
- have different numbers of neutrons - different masses (physical)
isotope symbol
mass number -> A
chemical symbol -> S
atomic number -> Z
elements atomic mass
weighted-average mass of isotopes of an element
atomic mass
calculated average mass of the isotopes of an element
periodic law
when elements are arranged in order of increasing atomic number, elements with similar properties occur at periodic regularly recurring interval
periodic table
a graphical display of the elements in order of increasing atomic number in which elements with similar properties fall in the same column of the display
group in periodic table
vertical column of elements
period in periodic table
horizontal row of elements
nonmetal
an element characterized by the absence of the properties of luster, thermal conductivity, electrical conductivity and malleability
the only nonmetal found as a liquid at room temperature are?
bromine and mercury
Subatomic particle
very small particle that are the building blocks from which atoms are made of
electron shell
a region of space about a nucleus that contains electrons that have approximately the same energy and that spend most of their time approximately the same distance from the nucleus
electron subshell
region of space within an electron shell that contains electrons that have the same energy
subshell size type letters and maximum electrons
s = 1 p = 6 d = 10 f = 14
electron orbitals
region of space within an electron subshell where an electron with a specific energy is most likely to be found
- orbitals maximum of electron is 2
ex - 14f has 7 orbitals
electron configuration
statement of how many electrons an atom has in each of its subshell
two most common classification systems of elements
- system based on selected physical properties of the elements - described as metal or non metal
- based on electron configurations of the elements - described as noble gas, representative, transition, or inner transition elements
noble gas elements
found in the far right column of the periodic table
- non metals
- all gases at room temperature
- little tendency to form chemical compound
- electron config ending in p6 (not helium)
noble gases: the most unreactive of all elements
helium, neon, and argon
representative elements
- all elements of the s and p areas of the periodic table, with exception of the noble gases
- complete s or partial p
transition elements
- all elements of the d area of the periodic table
- d subshell
inner transition elements
- all elements of the f area of the periodic table
- have in f sub
stable nucleus
a nucleus that does not easily undergo change
unstable nucleus
a nucleus that spontaneously undergoes change
radioactivity
the radiation spontaneously emitted from an unstable nucleus
radioactive atom
an atom with an unstable nucleus from which radiation is spontaneously emitted
radioactive decay
the process whereby an unstable nucleus undergoes change as a result of the emission of radiation
- not all decay at same rate
half-life
the time required for 1/2 of any given quantity of a radioactive substance to undergo decay
alpha particle
particle in which two protons and two neutrons are present
4 4
a = He
2 2
beta particle
- particle whose charge and mass are identical to those of an electron
o
ß
-1
gamma ray
- form of high energy radiation without mass or charge
0
Y
0
parent nucleus
- nucleus that undergoes decay in a radioactive decay process
daughter nucleus
nucleus that is produced as a result of a radioactive decay process
alpha particle decay equation
A 4 A-4
X–>a + Y
Z 2 Z-2
balanced nuclear equation
sums of the subscript (atomic numbers or particle charges) on both sides of the equation are equal, and the sums of the superscripts (mass number) on both sides of the equation are equal
