1. Early Models of the Atom
4.1
Early Models of the Atom
Early Models of the Atom
An __________ is the smallest particle of an element that _________ its ____________ in a chemical reaction.
Philosophers and scientists have proposed many ideas on the structure of atoms.

2. Early Models of the Atom
4.1
Early Models of the Atom
Democritus believed that atoms were ___________ and ________________.
Democritus’s ideas were limited because they didn’t explain ________________ ______________ and they lacked ___________________ support.

3. Early Models of the Atom
4.1
Early Models of the Atom
By using _______________ methods, Dalton transformed Democritus’s ideas on atoms into a ___________________ ______________________.
The result was Dalton’s _____________ theory.

4. Early Models of the Atom
4.1
Early Models of the Atom
All elements are composed of ______ __________ ____________ called __________.
Atoms of the same element are _________. The atoms of any one element are ____________ from those of any other element.
According to Dalton’s atomic theory, an element is composed of only one kind of atom, and a compound is composed of particles that are chemical combinations of different kinds of atoms. a) Atoms of element A are identical. b) Atoms of element B are identical, but differ from those of element A. c) Atoms of elements A and B can physically mix together. d) Atoms of elements A and B can chemically combine to form a compound. Interpreting Diagrams How does a mixture of atoms of different elements differ from a compound?

5. Early Models of the Atom
4.1
Early Models of the Atom
Atoms of different elements can physically mix together or can ____________ combine in simple ___________________ _____________ to form _________________________
Chemical reactions occur when atoms are __________ ___________ or _______________. 
Atoms of one element are ___________ changed into atoms of another element in a chemical
reaction.
According to Dalton’s atomic theory, an element is composed of only one kind of atom, and a compound is composed of particles that are chemical combinations of different kinds of atoms. a) Atoms of element A are identical. b) Atoms of element B are identical, but differ from those of element A. c) Atoms of elements A and B can physically mix together. d) Atoms of elements A and B can chemically combine to form a compound. Interpreting Diagrams How does a mixture of atoms of different elements differ from a compound?
Scientists used a scanning tunneling microscope to generate this image of iron atoms, shown in blue. The radius of this circle of atoms is just 7.13 × 10-9 m.

6. 4.1
Sizing up the Atom
Despite their small size, individual atoms are observable with instruments such as ______________ ________________ microscopes.