Key Concepts in Chemistry Flashcards
How has Dalton’s atomic model changed over time?
Dalton thought atoms were solid spheres but now we have discovered subatomic particles (protons, electrons, neutrons) that make up atoms.
What subatomic particles are found in the nucleus and what surrounds it?
Neutrons and protons are found in the nucleus, surrounded by electrons in shells.
What are the relative charges of protons, neutrons and electrons?
Protons: +1
Neutrons: 0
Electrons: -1
What are the relative masses of protons, neutrons and electrons?
Protons: 1
Neutrons: 1
Electrons: negligible
Why are atoms neutral?
Protons and electrons have equal but opposite charge and atoms have an equal amount of protons and electrons.
Is the nucleus large or small relative to the rest of the atom?
Tiny
What is the mass number of an atom?
The total number of protons and neutrons
What atomic feature defines an element?
All atoms of the same element have the same number of protons.
What is an isotope?
Different forms of the same element which have the same number of protons but a different number of neutrons.
What is the atomic number?
The number of protons in an atom
Why is the relative atomic mass sometimes a decimal?
If an element has more than one isotope, it’s relative atomic mass is the average of the mass numbers of all different isotopes, taking into account their abundance.
relative atomic mass =
(SUM(relative isotopic abundance*relative isotopic mass))/total abundance
What is an ion?
Charged particles
What is a cation and an anion?
Cations are positive ions; anions are negative
Are you able to draw dot and cross diagrams for ionic bonding (pg 21)?
Yes
