Chemical Changes And Structure #2: Periodic Table & Atomic Structure Flashcards
How are elements in the periodic table arranged?
In order of increasing atomic number
What can the periodic table be used to determine?
Whether an element is a metal or a non-metal
What can we do with the electron arrangement of the first 20 elements?
Write them
What does an atom have?
A nucleus
How many types of atom are in each element?
1
What does a nucleus contain?
- protons and neutrons
- electrons that orbit the nucleus
What is the charge of a proton?
One-positive
What is the charge of a neutron?
Neutral
What is the charge of an electron?
One-negative
What is the relative weight / amu of a proton?
1
What is the relative weight / amu of an electron?
Almost zero
What is the relative weight / amu of a neutron?
1
Where is the proton?
In the nucleus
Where is the neutron?
In the nucleus
Where is the electron? Why?
Orbiting the nucleus, it is negatively charged and so attracted to the positive nucleus - opposites attract
What is relative weight?
Atomic mass (amu)
Atomic number =
Number of protons , number of electrons
Mass number =
Number of protons and neutrons
How do we find the number of neutrons?
Mass number - atomic number
What is the charge of the nucleus?
Positive, because it’s positively and neutrally charged
What is nuclide notation used to show?
The atomic number, mass number (and charge) of atoms (ions) from which the number of protons, neutrons, and electrons can be determined
What is an isotope? (test question)
Atoms of the same element that have the same atomic number but a different mass number
Isotopes have the exact same…
Chemical properties as other atoms
What does it mean that isotopes have a different mass number?
Of the 118 atoms, some are heavier because they have a different amount of neutrons and so different mass numbers.
If atoms of the same element can have a different amount of neutrons, what else must be different?
Their mass
How do chemists use an average mass of the atoms in an element for calculations?
They take into account different isotopes and their relative abundance
What do elements in a group in the periodic table have in common?
Similar chemical properties
5 Properties of alkali metals
- Very reactive
- Soft
- Stored under oil
- Reaction with H20 = Alkaline solution
- Reaction with oxygen = metal oxide
4 properties of the transition metals
- hard and dense
- less reactive
- used as catalysts
- form coloured compounds
5 properties of the halogens
- diatomic elements
- All toxic
- flourine added to toothpaste to prevent decay
- chlorine sterilises swimming pools
- iodine treats wounds
2 Properties of noble gases
- not reactive at all
- least reactive of all the elements
Ways to remember how to work out nuclide notation
Atomic number = protons = electrons
Mass number = protons + neutrons
Neutrons = mass number - atomic number
What does RAM take into account?
Different isotopes and their relative abundance
Why do elements in a group have similar chemical properties?
They have the same number of outer electrons
How many electrons can the first energy level hold?
2
How many electrons can the 2nd and 3rd energy levels hold?
8 each
How are elements arranged in periods?
In order of increasing atomic number
When are ions formed?
When atoms gain or lose electrons
What happens when an atom gains an electron?
It becomes a negatively charged ion
What happens when an atom loses an electron?
It becomes a positively charged ion
Non metals gain electrons to become…
negatively charged ions
Metals lose electrons to become…
Positively charged ions
What do atoms achieve by forming ions?
The same arrangement as the nearest noble gas
Why are noble gases unreactive?
They have a stable outer electron arrangement
Something to note about group 7
Reactive non-metals
Something to note about Group 8
Un-reactive non-metals
