1.2.1 - The Atomic Model
No description yet. This curated deck is ready for daily study.
Card preview (13)
What are elements?
substances that can not be broken down into simpler components by chemical reactions
What is an atom?
the smallest unit of an element
What did John Dalton propose to explain that hydrogen and oxygen always combine in fixed proportions?
all matter is composed of atoms, atoms cannot be created nor destroyed, atoms of the same element are alike in every way, atoms of different elements are different, atoms can combine together to form molecules
How was it concluded that the nucleus was very small and the atom is mostly empty space?
Ernest Rutherford fired alpha particles at a piece of gold foil, most went straight through but some were deflected when the alpha particles collide and were repelled by a positive nucleus
Why are neutrons important for elements with more than one proton?
without neutrons, the charged protons would repel eachother and the nucleus would fall apart
What is the atomic number?
the number describing each element’s relative position on the periodic table and the number of protons
What is the atomic number represented by?
Z
What is the mass number of an element represented by?
A
What is the mass number?
protons + neutrons
What is responsible for a chemical change?
electrons only
What is an ion?
an atom whose protons are not balanced by the same number of electrons
What is a cation?
positive ion (lost electrons)
What is an anion?
negative ion (gained electrons)