Basic Chemistry Flashcards
What is an atom?
An atom is the smallest part of an element that has properties of that element
What is an element?
An element is a substance made of only one kind of atom; ex: O2
What is a molecule?
Two or more atoms chemically joined together; ex: H2O
What is a compound?
Two or more atoms chemically joined together
Are all compounds molecules?
Yes
Are all molecules compounds?
No
What two particles does each atom have in their nucleus?
Protons and neutrons
Where are electrons located in the electron cloud model?
In orbitals, outside the nucleus
What does molecular formula consist of?
- Symbols showing which elements are present
- Subscripts showing the number of atoms
- Coefficient showing the total number of molecules
What does structural formula show?
How the molecules are bonded together and arranged
What do electrons orbit?
The nucleus
What do energy shells need to be in order to be stable?
They need to be full
Chemical reactions occur when?
Valence electrons (in the outermost shell), share, gain, or lose electrons to fill the shell
Most atoms are stable when there are how many electrons in the outer shell?
8
When does a chemical bond form?
When atoms combine
Where is energy stored?
Between the bonds between atoms
When is energy released?
When the bonds are broken
Ionic bond
Loss or gain of electrons
Covalent bond
Sharing of electrons
Why do ionic bonds have an electrical charge?
They have an unequal number of protons and electrons
Loss of an electron makes the ion
Positive
Gain of an electron makes the ion
Negative
Covalent bonds - Single bond
One pair of electrons shared between 2 atoms
Covalent bonds - Double bond
Two pairs of electron shared between 2 atoms
