Atoms & Matter
What is an atom?
The smallest unit of an element that retains the properties of that element.
Who proposed the first atomic theory?
John Dalton.
What information does the atomic number provide?
The number of protons in the nucleus of an atom.
What is the difference between an element and a compound?
An element is a pure substance made of only one type of atom, while a compound is made of two or more different types of atoms chemically bonded together.
What did Dalton’s model of the atom look like?
A solid, indivisible sphere.
What is a group in the periodic table?
A vertical column that contains elements with similar chemical properties.
Provide an example of a mixture.
Salad, air, or saltwater.
Describe Thomson's model of the atom.
The "plum pudding" model, where negatively charged electrons are embedded in a positively charged "soup."
Name a property of metals.
Good conductors of heat and electricity, malleability, and ductility.
What are chemical symbols?
Abbreviations used to represent elements, typically consisting of one or two letters, with the first letter capitalized (e.g., H for hydrogen).
What is Rutherford's main discovery?
The nucleus of the atom is small, dense, and positively charged.
What are metalloids?
Elements with properties intermediate between metals and nonmetals, found along the zig-zag line on the periodic table.
How do chemical formulas represent compounds?
They show the elements in a compound and the ratio of the atoms of each element (e.g., H₂O for water indicates two hydrogen atoms and one oxygen atom).
Explain Bohr's model of the atom.
Electrons orbit the nucleus in fixed paths or energy levels.
Identify a noble gas and its properties.
Neon; it is colorless, odorless, and inert (non-reactive under standard conditions)