atomic structure Flashcards
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.
What is the symbol for carbon?
C
What is the symbol for iron?
Fe
What are isotopes?
Isotopes are different forms of the same element that have the same number of protons but a different number of neutrons.
What do isotopes have in common?
Isotopes have the same atomic number but different mass numbers.
Give an example of a pair of isotopes.
Carbon-12 and carbon-13.
How is the number of neutrons in an isotope calculated?
The number of neutrons is the mass number minus the atomic number.
What is relative atomic mass?
Relative atomic mass is an average mass of an element, taking into account the different masses and abundances of all its isotopes.
What formula is used to calculate relative atomic mass?
Relative atomic mass (A) = sum of (isotope abundance X isotope mass number) / sum of abundances of all the isotopes.
What is the atomic structure of an element?
A substance consists of atoms which all have the same number of protons and electrons but different numbers of neutrons.
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.
What is the symbol for carbon?
C
What is the symbol for iron?
Fe
What are isotopes?
Isotopes are different forms of the same element that have the same number of protons but a different number of neutrons.
What do isotopes have in common?
Isotopes have the same atomic number but different mass numbers.
Give an example of a pair of isotopes.
Carbon-12 and carbon-13.
How is the number of neutrons in an isotope calculated?
The number of neutrons is the mass number minus the atomic number.
What formula is used to calculate relative atomic mass?
Relative atomic mass (A) = sum of (isotope abundance X isotope mass number) / sum of abundances of all the isotopes.
What is the atomic structure of an element?
A substance consists of atoms which all have the same number of protons and electrons but different numbers of neutrons.
What are compounds?
Substances formed from two or more elements held together by chemical bonds.
What happens when elements react?
Atoms combine with other atoms to form compounds.
What are the fixed proportions in a compound?
The atoms of each element are in fixed proportions throughout the compound.
What is involved in making chemical bonds?
Atoms give away, take, or share electrons.
What remains unaffected when a bond is made?
The nuclei of the atoms.
What is required to separate the original elements of a compound?
A chemical reaction.
What do metal atoms do in ionic bonding?
Lose electrons to form positive ions.
What do non-metal atoms do in ionic bonding?
Gain electrons to form negative ions.
What is the attraction in ionic bonding?
The opposite charges of the ions are strongly attracted to each other.
Give an example of compounds that are bonded ionically.
- Sodium chloride
- Magnesium oxide
- Calcium oxide
What is covalent bonding?
Each atom shares an electron with another atom.
Give examples of compounds that are bonded covalently.
- Hydrogen chloride gas
- Carbon monoxide
- Water
How do the properties of a compound compare to the original elements?
The properties are usually totally different.
What is the formula for carbon dioxide?
CO2
What does the formula for sulfuric acid represent?
H2SO4 - contains 2 hydrogen atoms, 1 sulfur atom, and 4 oxygen atoms.
What does a bracket in a chemical formula indicate?
The little number outside the bracket applies to everything inside the brackets.
What is the formula for sodium chloride?
NaCl
What is the formula for ammonia?
NH3
What is the formula for water?
H2O
What is the formula for hydrochloric acid?
HCl
What is the formula for sulfuric acid?
H2SO4
What is symbol equation in chemistry?
A way to show a chemical change using symbols.
What are reactants in a chemical equation?
The molecules on the left side of the equation.
What is the significance of chemical equations?
They represent the reactants and products in a chemical change.
What is an example of a compound formed from a metal and a non-metal?
Iron sulfide.
Fill in the blank: The property of iron sulfide is _______.
dull grey solid lump.
True or False: The properties of a compound are similar to the properties of the original elements.
False
What is electron transfer?
Electron transfer involves the movement of electrons between atoms, resulting in the formation of ions.
What is ionic bonding?
Ionic bonding is the transfer of electrons from a metal to a non-metal, resulting in the formation of oppositely charged ions that attract each other.
How do dot and cross diagrams represent ionic compounds?
Dot and cross diagrams show the arrangement of electrons in an atom or ion, with dots representing one atom’s electrons and crosses representing another’s.
What happens in the formation of Sodium Chloride (NaCl)?
The sodium atom loses its outer electron to become Na+, while the chlorine atom gains that electron to become Cl-.
What occurs in the formation of Magnesium Oxide (MgO)?
The magnesium atom loses two outer electrons to become Mg2+, while the oxygen atom gains those electrons to become O2-.
How is Magnesium Chloride (MgCl2) formed?
The magnesium atom loses two outer electrons to become Mg2+, and two chlorine atoms each gain one electron to become two Cl- ions.
What is the process for forming Sodium Oxide (Na2O)?
Two sodium atoms each lose their single outer electron to become Na+ ions, while the oxygen atom gains two electrons to become O2-.
What are the limitations of dot and cross diagrams?
Dot and cross diagrams do not show the structure of the compound, the size of the ions, or how they are arranged.
