Elements Flashcards
Atoms and elements are considered as the what of chemistry?
Building blocks.
Atoms contain which sub-atomic particles?
Protons, neutrons and electrons.
A substance that is made of one kind of atom is called an…
…element.
Elements can be shown in which table?
The Periodic Table.
Every letter on the periodic table represents what?
An element. Eg: O for oxygen and Na for sodium.
What type of sub-atomic particles do atomic nuclei consist of?
Protons and neutrons.
What are the relative charges of the sub-atomic particles?
Proton = +1 Neutron = 0 Electron = -1
True or false, in an atom the number of protons is equal to the number of electrons?
True, because this gives each atom an overall charge of 0.
Electrons are not part of the atomic nucleus, but still part of the atom, so where are they?
They orbit in rings around the nucleus.
All atoms of the same element have the same number of what?
Protons.
What is the atomic number?
The number of protons in an atom of an element (equal to the number of electrons).
What is the mass number?
The number of protons plus the number of electrons in an atom of an element.
What are electron shells?
In an atom electrons occupy different energy levels. Each electron is at a particular energy level (in a particular shell). Electrons occupy the lowest available energy level (innermost shell).
Elements in the same groups in the periodic table have what in common?
They have the same number of electrons in their highest energy level (shell) which gives them similar chemical properties.
Elements in Group 0 are called noble gases. Why?
They have full outer energy levels (shells) making them unreactive.
What happens when elements react?
Atoms join together to form compounds. This can take place by sharing or taking electrons to form molecules or ions. Compounds formed from metals and non-metals consist of ions whereas compounds formed of non-metals consist of molecules. In molecules the atoms are held together by covalent bonds.
Chemical reactions can be represented how?
In word or symbol equations.
During chemical reactions, what happens to the mass?
The overall mass remains the same because no atoms are lost, so the mass of the products is equal to the mass of the reactants.
