Chapter 1 - Atoms and Elements Flashcards
What does the periodic table include?
All discovered elements in the universe
How are elements organized in the periodic table?
Based on chemical properties
What does the atomic number represent?
protons in the atom
In a neutral atom, how many electrons are there compared to protons?
protons = # electrons
Who discovered the neutron?
Chadwick
Where is the neutron located?
In the nucleus
What is the formula to determine the number of neutrons?
Atomic Mass – Atomic # = # neutrons
What are isotopes?
Atoms of the same element with different numbers of neutrons
Do isotopes have the same number of electrons?
Yes
How do scientists distinguish between isotopes?
By stating the combined total of protons and neutrons (mass number)
What is the atomic mass of Calcium (Ca)?
40.08
Where are metals located on the periodic table?
On the left-hand side of the staircase
What are the properties of metals?
- Conduct heat and electricity
- Ductile
- Malleable
- Shiny
- Solid at room temperature (except Mercury)
- React with acid (produces Hydrogen gas)
Where are non-metals located on the periodic table?
On the right side of the staircase
What are the properties of non-metals?
- Do not conduct heat or electricity
- Many are gases at room temperature
- The few that are solids are easily reduced to powder
Where are metalloids located on the periodic table?
Found touching the staircase
What are the properties of metalloids?
- Have properties of both metals and non-metals
- Semiconductors
What is a family/group in the periodic table?
Columns of the periodic table
What do elements in the same family/group have in common?
Similar chemical properties
How many valence electrons do elements in Group IA have?
1 valence electron
What are alkali metals?
Group IA elements (except hydrogen) that react with air and water
What is the reactivity trend of alkali metals?
Get more reactive as you go DOWN the column
How many valence electrons do elements in Group IIA have?
2 valence electrons
What are alkaline earth metals?
Group IIA elements that are highly malleable and burn easily
How many valence electrons do elements in Group VIIA have?
7 valence electrons
What do halogens form when combined with alkali metals?
Salts
How many valence electrons do noble gases have?
8 valence electrons (except Helium)
What is the stability of noble gases?
Stable and react minimally
What does the period number indicate in the periodic table?
The number of energy levels (orbits or shells) of an atom
