atomic structures Flashcards
Define a compound
Contain two or more elements chemically combined in fixed proportions and can be represented by formulae using the symbols of the atoms from which they were formed.
Examples include water (H2O) and sodium chloride (NaCl).
Define a mixture
Consists of two or more elements or compounds not chemically combined together.
Examples include air and salad.
State the approximate radius of an atom
About 0.1 nm.
1 nm = 1x10^-9 m.
Describe the current model of the atom
Electrons occupy energy levels (shells) surrounding the nucleus.
This model incorporates quantum mechanics.
What does the atomic number of an atom represent?
Number of protons in an atom.
Atoms of the same element have the same number of protons.
What does the mass number of an atom represent?
The sum of protons and neutrons in an atom.
Describe the plum pudding model of the atom
Proposed that atoms are made of a positive ‘soup’ with negatively charged electrons embedded within.
This model was introduced by JJ Thompson.
State the conclusions of the alpha scattering experiment
Atoms have a small, dense nucleus that is positively charged, with electrons surrounding it.
Conducted by Geiger and Marsden.
How did Niels Bohr adapt the model of the atom?
Proposed that electrons occupy fixed energy levels (shells) around the nucleus.
What did James Chadwick do to change the model of the atom?
Discovered the neutron, leading to a more accurate atomic model.
State the electrical charges of each subatomic particle
Proton: +1, Neutron: 0, Electron: -1.
State the relative mass of each subatomic particle
Proton: 1, Neutron: 1, Electron: 1/1840.
Fill in the blank: A _______ is a substance made of only one type of atom.
Element
Fill in the blank: Atoms of the same element with a different number of neutrons are called _______.
Isotopes
What is relative atomic mass?
The average mass of an atom of an element, taking into account the percentage of each isotope.
What is the naming convention for compounds made of two elements?
Use the suffix ‘ide’.
Example: Na2S is sodium sulfide.
What is the naming convention for compounds that include oxygen?
Use the suffix ‘ate’.
Example: Na2SO4 is sodium sulfate.
True or False: Atoms can be chemically broken down into simpler substances.
False
