Chapter 1 Definitions Flashcards
alpha particles
a particle containing two protons and two neutrons, aka helium nucleus
element
a pure substance made up of atom of the same atomic number
periodic tabe
a chart of the elements, arranged in increasing atomic number; it is organised into groups and periods to show trends in the elements
synthetic element
element that does on exist in nature, but has been made in a laboratory
atomic number
the number of protons in an atom
mass number
the total number of protons and neutrons in an atom
electrostatic attraction
a force that pulls the particles together when they have an opposite charge
electrostatic repulsion
a force that pushes particles apart when they have an identical change
strong nuclear force
an attractive force that exists between particles in the nucleus; it is a short-range force acting only on adjacent particles
isotopes
different forms of an element with the same number of protons but different number of neutrons
chemical properties
a property of a substance relating to its ability to change to new substances during chemical reactions
relative atomic mass
the mean mass of an element that takes into account the isotope masses and the relative abundance on Earth; it is measured against carbon-12
physical properties
an observable feature of a substance that can be measured without changing the identity of the substance, such as colour, density, hardness
radioactive decay
the spontaneous disintegration of an atom due to instability in the nucleus, during which particles or electromagnetic radiation are released
periods
a horizontal row of elements in the periodic table that gives information on the number of energy level s occupied by electrons
groups
a vertical column in the periodic table that gives information on number of valence shell electrons and trends between atoms
alkali metals
the common name for elements found in group 1 of the periodic table
transition elements
elements found between groups 2 and 13 in the periodic table, also known as the d-block elements
reactivity
the likelihood of an element or substance undergoing a chemical reaction
metalloid
an element that has properties of both metals and non metals