atomic structure Flashcards
(83 cards)
What are all substances made of?
Atoms
Atoms are extremely small and cannot be seen even with a microscope.
How many atoms are approximately in a 50p piece?
About 7.4 × 10^21 atoms
This number illustrates the vast quantity of atoms in even small objects.
What is the radius of an atom?
About 0.1 nanometres (1 × 10^-10 m)
A nanometre is one billionth of a metre.
What does the nucleus of an atom contain?
Protons and neutrons
The nucleus is at the center of the atom.
What charge does the nucleus have and why?
Positive charge due to protons
Protons are positively charged particles.
What is the mass concentration in an atom?
Almost the whole mass of the atom is in the nucleus
This indicates that the nucleus is very dense.
What are the three main particles in an atom?
- Protons
- Neutrons
- Electrons
What is the charge and mass of protons?
Charge: +1, Mass: Heavy
Protons contribute significantly to the mass of an atom.
What is the charge and mass of neutrons?
Charge: Neutral, Mass: Heavy
Neutrons also contribute to the mass but do not affect the charge.
What is the charge and relative mass of electrons?
Charge: -1, Mass: Very small
Electron mass is often considered negligible.
Where do electrons move within an atom?
Around the nucleus in electron shells
The arrangement of electrons determines the atom’s size.
What is true about the number of protons and electrons in an atom?
They are equal, making the atom neutral
This balance results in no overall charge.
What happens in an ion?
The number of protons does not equal the number of electrons
This results in a net charge.
How can you find the number of neutrons in an atom?
Subtract the atomic number from the mass number
The atomic number indicates protons, and the mass number is the total of protons and neutrons.
What does the atomic number represent?
The number of protons in an atom
It also identifies the element.
What does the mass number indicate?
The total number of protons and neutrons
This number is essential for identifying isotopes.
What is the mass number of gallium?
70
This includes both protons and neutrons.
Fill in the blank: An atom that has lost or gained electrons is called a _______.
Ion
Ions can be positively or negatively charged depending on electron loss or gain.
What is an element?
An element is a substance made up of atoms that all have the same number of protons in their nucleus.
How does the number of protons affect the type of atom?
The number of protons in the nucleus decides what type of atom it is.
What is the atomic number of hydrogen and helium?
Hydrogen has one proton, and helium has two protons.
What is the significance of having the same number of protons in a substance?
If a substance only contains atoms with the same number of protons, it is called an element.
How many different elements are there approximately?
There are about 100 different elements.
What is the purpose of symbols in chemistry?
Atoms of each element can be represented by a one or two letter symbol, which serves as shorthand for the element’s full name.