Inv6.Exp1 Test

1. According to Dalton's atomic theory, what is true about atoms of the same element?

• They have different masses
• They are identical to one another
• They have different chemical properties
• They can be divided into smaller particles

2. What was a major modification to Dalton's original atomic theory?

• The discovery that atoms can be divided into subatomic particles
• The discovery that atoms are spherical
• The proof that atoms don't exist
• The finding that atoms can't bond together

3. What is the term for different molecular arrangements of the same element?

• Compounds
• Molecules
• Allotropes
• Isotopes

4. What fraction of an atom's mass did Rutherford find was concentrated in the nucleus?

• About 50%
• Less than 90%
• More than 99%
• Exactly 75%

6. How does the mass of an electron compare to the lightest known atom?

• It's about 1/1800th the mass
• It's exactly the same mass
• It's twice the mass
• It's half the mass

8. What is the modern view of electrons in an atom?

• They are fixed particles in specific locations
• They orbit like planets around the sun
• They are waves of probable positions in orbitals
• They float randomly through the atom

10. Which scientist proposed that gases are composed of individual particles?

• Ernest Rutherford
• J.J. Thomson
• Niels Bohr
• John Dalton

12. In the chemical formula H2O, what does the subscript 2 indicate?

• Two oxygen atoms
• Two hydrogen atoms
• Two molecules
• Two compounds

13. What distinguishes a compound from other molecules?

• It contains only one type of atom
• It contains different types of atoms
• It cannot be broken down
• It exists only in gas form

19. What aspect of Dalton's atomic theory remains fundamental to modern chemistry?

• Atoms are indivisible
• Atoms are solid spheres
• Elements consist of atoms
• Atoms have no substructure