The Atom
How can we describe atoms?
Atoms described by atomic numbers and by mass numbers.
What are elements?
Elements are basic substances of matter.
What is a chemical reaction?
A chemical reaction is the process in which atoms are rearranged to produce new substances.
Number of atoms of each element in H2O?
2 Hydrogen atoms
1 Oxygen atoms
What did John Dalton's theory state?
His theory stated that all matter is made up of atoms.
What is an atom?
An atom is the smallest particle into which an element can be divided and still be the same element.
Why is the table of elements called "periodic"?
When Dmitri Mendeleev arranged the elements by the order of increasing atomic mass, the properties of the elements were in regularly repeating pattern, periodic.
What are signs of a chemical reaction?
Color change, odor change, precipitate formation, and appearance of gas bubbles.
what is the chemical symbol of Gold?
Au is the chemical symbol for Gold
what did Earnest Rutherford prove with his experiment?
He proved that all atoms have a nucleus.
Even though atoms can become smaller, why are they still the basic smallest unit?
Atoms are still the basic smallest unit because they are the smallest unit which has chemical porperties of an element.
Who re-arranged the periodic table by atomic number like a calendar of protons and electrons?
Henry Moseley
How are chemical reactions modeled?
They can be modeled using chemical formulas, subscripts, and chemical equations.
Number of atoms of each element in CaO?
1 Calcium
1 Oxygen
What did J.J.Thomson prove with his experiment?
He proved that atoms are made up of even smaller particles. The particles smaller than atoms have negative charges, which are known as electrons.
What are the parts of an atom?
Protons, neutrons, and the electron cloud.
What information does each square contain on the periodic table?
The atomic number, chemical symbol, chemical name, and average atomic mass.
What affects the rate of reactions?
Factors that affect reaction rates include concentration, surface area, temperature, and the presence of a catalyst.
The atomic number for Cobalt is 27, how many protons are in cobalt?
27 protons are in Cobalt
How did Niels Bohr's belief help with discovering something new about atoms?
His belief helped predict chemical properties of atoms.
Why did Democritus name these particles "atoms"?
Democritus thought that soon a particles would be too small to be cut in half, that is why he names those particles atomos, a Greek word for "not able to be divided".
How are the elements arranged on the periodic table?
Metals, nonmetals, and metalloids.
Elements in each column have similar properties: group
Elements in each row follow periodic trends: period
Elements are arranged in order of increasing atomic number.
What does the Law of Conservation of Mass and Energy state?
The Law of Conservation of Mass states that matter is neither created nor destroyed.
The Law of Conservation of Energy states that energy cannot be created nor destroyed.
True/False: Some elements have the same atomic number.
False
How did Dmitri Mendeleev and Henry Moseley contribute to the periodic table?
Dmitri Mendeleev arranged the elements by the order of increasing atomic mass, the properties of the elements were in regularly repeating pattern.
Henry Moseley rearranged the periodic tables by atomic number.