Recipe book of the Universe Flashcards
Solar system definition
Gravitationally bound system of the sun and the objects that orbit around it
Galaxy
Huge collection of gas dust, billions of stars and their solar systems, held together by gravity
Star
Large, spherical celestial body consisting of a mass of gas that is hot enough to system nuclear fusion, thus producing radiant energy
Nebulae
Cloud of gas and dust in outer space, visible in night sky as an indistinct bright patch or as a dark silhouette against other luminous matter.
Relate colours of stars to their age
- Younger stars: Blue, brighter, heavier, bigger, hotter
- Older stars: Red, less bright, lightest, smaller, less hot
- Older stars reduce the energy they emit as they run out of hydrogen
Electron description
- Negative charge
- Located in energy shells around nucleus
- Responsible for reactivity
Neutrons description
- Neutral charge
- Located in nucleus
- Holds together nucleus
Protons description
- Positive charge
- Located inside nucleus
- Determines atom identity
What does the atomic number represent?
Amount of protons
What is the chemical symbol?
The shortened version of an element’s name
What is the atomic mass?
Approximately equivalent to number of protons and neutrons in an atom
Group meaning
How many electrons are on the valence shell of an atom, displayed vertically on the periodic table
Period meaning
Number of electron shells an atom has, displayed horizontally on the periodic table
General properties of elements on left side of periodic table (group 1 and 2)
- Low melting points
- Highly reactive
- Malleable, solid metals
General properties of elements on right side of periodic table (group 7 and 8)
- Low boiling points
- Highly reactive (except noble gases)
- Non-metals