Chapter 3-Atomic structure Flashcards
What is an atom?
An atom is the smallest piece of an element that can still be recognised as that element (it cannot be broken by a chemical reaction).
What is a molecule?
A molecule is small group of two or more atoms chemically bonded (by covalent bonds). The atoms that make up a molecule can be from the same elements or different elements.
What are the sub-atomic particles called?
Protons, neutrons and electrons
What is the centre of an atom called and what are the sub-atomic particles found there?
The centre of an atom is called the nucleus and protons and neutrons are found there.
Where are electrons found in an atom?
Electrons are found in shells orbiting the nucleus.
What is the relative mass of proton?
The relative mass of a proton is 1.
What is the relative charge of a proton?
The relative charge of a proton is +1.
What is the relative mass of a neutron?
The relative mass of a neutron is 1.
What is the relative charge of a neutron?
The relative charge of a neutron is 0.
What is the relative mass of an electron?
The relative mass of an electron is 1/1836 (almost 0).
What is the relative charge of an electron?
The relative charge of an electron is -1.
What makes atoms neutral?
In an atom, the number of electrons (negative) is equal to the number of protons (positive) so atoms are neutral (they have no overall electrical charge).
What is the atomic number?
The number of protons in an atom’s nucleus is called its atomic number or proton number.
*atomic number=number of protons
What is the mass number?
The mass number (sometimes known as the nucleon number) tells us the total number of protons and neutrons in the nucleus of the atom.
*mass number=number of protons+number of neutrons
How do you find out the number of neutrons in an electron?
*number of neutrons=mass number-atomic number
How can APEMAN be used to find the number of protons, neutrons and electrons in an atom?
Atomic number (smallest)= Protons= Electrons= Mass number (biggest)- Atomic number (smallest)= Neutrons
What are isotopes?
Isotopes are atoms (of the same element) which have the same atomic number but different mass numbers. They have the same number of protons but different numbers of neutrons.
Why do isotopes have the same chemical properties?
Their varying numbers of neutrons make no difference to their chemical reactions. The chemical properties are controlled by the number and arrangement of the electrons; that is identical for all the isotopes.
What is Relative Atomic Mass (RAM)?
The average mass of an atom, taking into account the amount of each isotope present in a naturally occurring sample of an element. This type of average is called a weighted average or a weighted mean.
How do you calculate the RAM of an element from the relative abundances of its isotopes?
For an element containing 2 isotopes A and B:
RAM=(% of isotope A x mass of isotope A) + (% of isotope B x mass of isotope B) / 100
What are the elements in the Periodic Table arranged in order of?
They are arranged in order of atomic number, in groups and periods.
How many electrons can the first shell/energy level hold?
2 electrons
How many electrons can the second shell/energy level hold?
8 electrons
How many electrons can the third shell/energy level hold?
A maximum of 8 electrons for the first 20 elements.
Which shells/energy levels are filled first?
Lower energy levels are always filled before higher ones; the shells closest to the nucleus are filled first.
What is the arrangement of electrons in an atom called?
The arrangement of electrons in an atom is called its electronic configuration.
How do you draw diagrams of electronic configurations?
When we draw diagrams of electronic configurations, we draw circles to represent the shells (energy levels); dots/crosses are then drawn on the circles to represent the electrons.
