1st unit Flashcards
A material made up of two or more kinds of atoms in a constant proportion
Compound
Are elements and compounds pure substances?
Yes
An evenly mixed mixture/solution
Homogeneous
an unevenly mixed, clumpy solution
Heterogeneous mixture
A change where no new substances are made, and in can be undone.
Physical change
A change where a new substance is created and it cannot be undone
Chemical change
What is the size of an individual atom?
10^-10 m
What is the size of the nucleus of an atom?
10^-15 m
How many times smaller than the whole atom is the nucleus?
100,000 times smaller
What two particles determine the mass of an atom?
Protons and neutrons
What two particles determine the charge of an atom?
Protons and electrons
What are some characteristics of metals?
Metals tend to loose electrons and have positive ions called cations
What are some characteristics of non metals?
Non metals tend to gain electrons and have negative ions called anions
A material made up of one kind of atom
Element
Alkali metals have ____ ions
1+
Positron decay
Proton becomes a neutron
A positron has the same massas an electron, but opposite charge (positive)
