Science: Physical & Chemical Changes and Bonding

Question 1

What is a physical change?

Answer 1

a change in physical property (physical property: state of matter, color, temperature, density, etc.)
Examples: sugar and water, torn paper, food coloring and water, melting ice cubes

Question 2

What is a chemical change?

Answer 2

something that involves change in an element’s electrons
Examples: burned paper, sulfuric acid and sugar
Signs: fire, gas, color change, bubbling

Question 3

What are valence electrons?

Answer 3

the electrons in the outermost shell, or energy level, of an atom

Question 4

What is the octet rule?

Answer 4

the tendency of atoms to prefer to have eight electrons in the valence shell

Question 5

Are metal ions positively or negatively charged?

Answer 5

Metal ions are always positively charged