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