The periodic table Flashcards
Recall the chemical symbols of some common elements.
Hydrogen: H
Oxygen: O
Carbon: C
Nitrogen: N
Sodium: Na
Magnesium: Mg
Chlorine: Cl
Iron: Fe
Copper: Cu
Zinc: Zn
Describe how Mendeleev arranged elements into a periodic table.
Mendeleev arranged elements by increasing atomic mass.
He placed elements with similar chemical properties into columns (groups).
He left gaps for undiscovered elements, predicting their properties.
Describe how Mendeleev predicted the existence and properties of some elements yet to be discovered.
Mendeleev noticed patterns in the properties of known elements.
He left gaps in his periodic table and predicted that new elements would be discovered to fill these gaps.
For example, he predicted the properties of germanium, which was discovered later.
Explain how Mendeleev’s early ideas were supported by later evidence.
Mendeleev’s predictions were confirmed when new elements were discovered that matched his predictions.
For example, the discovery of elements like gallium and germanium supported his table.
When scientists discovered the atomic number, it became clear that elements should be arranged by atomic number, not mass, aligning with Mendeleev’s idea of patterns.
Explain some problems Mendeleev had when ordering the elements.
Some elements didn’t fit perfectly into his table when ordered strictly by atomic mass.
For example, iodine has a higher atomic mass than tellurium, but tellurium was placed before iodine based on their properties.
This issue was later resolved with the discovery of the atomic number.
Explain the meaning of the term ‘atomic number’.
The atomic number is the number of protons in the nucleus of an atom.
It determines the identity of an element and its position in the periodic table.
Describe how the elements are arranged in the modern periodic table.
Elements are arranged by increasing atomic number.
Elements in the same group have similar chemical properties and the same number of electrons in their outer shell.
The periods (rows) represent elements with the same number of electron shells.
Recall the positions of metals and non-metals in the periodic table.
Metals are located on the left and center of the periodic table.
Non-metals are on the right side of the periodic table.
State what the term ‘electronic configuration’ means.
Electronic configuration describes how electrons are arranged in an atom’s shells or energy levels.
For example, sodium (Na) has the electronic configuration 2.8.1.
Show electronic configurations in the form 2.8.1 and as diagrams.
The electronic configuration 2.8.1 means:
2 electrons in the first shell
8 electrons in the second shell
1 electron in the third shell
As a diagram, represent each shell as a circle around the nucleus with dots or crosses showing the electrons.
Predict the electronic configurations of the elements hydrogen to calcium.
Hydrogen (H): 1
Helium (He): 2
Lithium (Li): 2.1
Beryllium (Be): 2.2
Boron (B): 2.3
Carbon (C): 2.4
Nitrogen (N): 2.5
Oxygen (O): 2.6
Fluorine (F): 2.7
Neon (Ne): 2.8
Sodium (Na): 2.8.1
Magnesium (Mg): 2.8.2
Aluminium (Al): 2.8.3
Silicon (Si): 2.8.4
Phosphorus (P): 2.8.5
Sulfur (S): 2.8.6
Chlorine (Cl): 2.8.7
Argon (Ar): 2.8.8
Potassium (K): 2.8.8.1
Calcium (Ca): 2.8.8.2
Explain the links between an element’s position in the periodic table and its electronic configuration.
An element’s group number corresponds to the number of electrons in its outer shell.
E.g., Group 1 elements have 1 electron in the outer shell.
The period number indicates the number of electron shells.
E.g., Elements in period 3 have 3 electron shells.
Recall the positions of metals and non-metals in the periodic table.
Metals are found on the left side and in the middle.
Non-metals are on the right side of the periodic table.
