Atomic Theory
Who proposed the atomic theory?
John Dalton
What are the energy levels in the Bohr model called?
Shells
What is an element?
A pure substance that cannot be broken down into simpler substances by chemical means.
How are elements within a group (family) on the periodic table related?
They have similar properties.
What is a molecule?
A group of atoms bonded together.
What did John Dalton's atomic theory state?
Matter is composed of indivisible atoms.
Where do electrons occupy in the Bohr model?
The outermost energy level (valence shell)
How are elements organized in the periodic table?
Based on their atomic number and properties.
What are periods on the periodic table?
Horizontal rows of elements.
How are molecules different from compounds?
Molecules can be made up of the same type of atom or different types of atoms, while compounds are made up of different elements.
What significant discovery did Ernest Rutherford make about the atom?
He proposed the existence of the nucleus.
What determines the chemical properties of an element according to the Bohr model?
The arrangement of electrons in the valence shell
What are compounds?
Substances made up of two or more different elements chemically combined.
What are ions?
Charged atoms formed by gaining or losing electrons.
What are ionic compounds?
Compounds formed through the transfer of electrons between atoms.
What is the tiny dense region at the center of an atom called?
Nucleus
What is the outermost energy level of an atom called?
Valence shell
Give an example of an element and its symbol.
Sodium (Na) or Magnesium (Mg)
Explain how atoms become ions.
By gaining or losing electrons, atoms acquire a positive or negative charge.
How are chemical formulas used to represent compounds?
Chemical formulas use symbols and subscripts to represent the composition of compounds.
How did the Bohr model expand on Rutherford's work?
It proposed that electrons are arranged in energy levels, or shells, around the nucleus.
How does the arrangement of electrons in the valence shell affect the chemical properties of an element?
It determines the chemical properties of an element.
What is the periodic table organized into?
Groups (families) and periods.
What are charged atoms called?
Ions.
What are cations and anions?
Cations are positively charged ions, and anions are negatively charged ions.