Unit 1 Part 1 Flashcards
What is the difference between a physical and chemical change?
Physical changes are usually reversible (eg: changes of state).
Chemical changes are usually permanent and always produce a new substance.
Define Exothermic
Define Endothermic
Exothermic : Releases heat
Endothermic : Takes in heat
Define a catalyst
Catalysts are used to speed up a reaction rate which can be recovered unchanged.
Equation to measure rate of reaction
change in property
——————————
change in time
Describe the structure of an atom
Nucleus contains protons and neutrons. Electrons orbit around in different energy levels.
What are ions?
A changed particle
How are ions formed?
When an atom gains or loses electrons
Why do atoms for ions?
to achieve a stable electron arrangement
What can be said of the balance of protons and electrons in an atom compared to an ion?
atoms have equal amounts of protons to electrons
ions don’t have an equal amount for protons and electrons
Why are atoms neutral?
the protons and electrons cancel out
What’s the electron arrangement of any atom?
2
8
8
18
In Nuclide notation where does the mass number go?
Top left
How do you find the mass number?
Number of protons + number of electrons
In nuclide notation where do you find the atomic number?
Bottom left
How do you find the atomic number?
Number of protons
What are isotopes?
Atoms of the same element which have different mass numbers
Isotopes have different numbers of neutrons
On the periodic table, where do you find the atomic number
Above the letter
What’s the valency equal to?
valency = charge