science term 1 2024 Flashcards
A heterogenous mixture is…?
a mixture that is NOT evenly distributed
a homogenous mixture is…?
a mixture that IS evenly distributed
Explain the difference between an element and a compound.
An element is a substance made up of only one type of atom, while a compound is a substance made up of two or more different types of atoms chemically bonded together.
How are elements organized on the periodic table?
Elements are organized on the periodic table based on their atomic number and chemical properties. They are arranged in rows (periods) and columns (groups) according to similar properties.
(True or False) Compounds can be separated into their constituent elements by physical means
False
(True or False)
The chemical formula for water is H₃O.
False
(True or false)
Elements can combine in different ratios to form different compounds
True
(True or False)
All substances are either elements or compounds
False
Which of the following is an example of a compound?
a) Oxygen (O)
b) Hydrogen (H)
c) Water (H₂O)
- c) Water (H₂O)
How are elements represented on the periodic table?
a) By their chemical formula.
b) By their atomic number and symbol.
c) By their molecular structure.
b) By their atomic number and symbol.
The smallest particle of an element is called a ________.
atom
A chemical bond is a force that holds ________ together.
atoms
A substance made up of two or more elements chemically combined in a fixed ratio is called a ________.
compound
The chemical formula for table salt (sodium chloride) is ________
NaCl
Describe John Dalton’s atomic theory and its key principles.
John Dalton’s atomic theory proposed that atoms are indivisible and indestructible particles. It also suggested that atoms of different elements are different and that chemical reactions involve the rearrangement of atoms.
Explain the major contributions of Niels Bohr to the atomic model
Niels Bohr’s major contribution was the proposal of a model where electrons orbit the nucleus in fixed energy levels or shells. He also introduced the idea that electrons can jump between these energy levels by absorbing or emitting energy.
How did the discovery of the electron impact the understanding of the atom?
The discovery of the electron by J.J. Thomson led to the understanding that atoms are not indivisible as proposed by Dalton but are composed of smaller particles. This discovery paved the way for further exploration of atomic structure.
The ________ model proposed that atoms are made up of a positively charged nucleus surrounded by negatively charged electrons.
bohr
In Rutherford’s gold foil experiment, most alpha particles passed through the foil, indicating that atoms are mostly ________.
empty space
The modern atomic model describes the atom as a nucleus composed of protons and ________ surrounded by orbiting electrons.
neutrons
is a proton
-negatively charged
-positively charged
-neutrally charged
positively charged
is an electron
-negatively charged
-positively charged
-neutrally charged
negatively charged
is a neutron
-negatively charged
-positively charged
-neutrally charged
neutrally charged
The ancient Greeks proposed the concept of the atom as the smallest indivisible particle.
(True/False)
true
The plum pudding model suggested that atoms are composed of a positively charged nucleus surrounded by negatively charged electrons.
(True/False)
false
The discovery of the neutron led to the modern atomic model. (True/False)
false
John Dalton’s atomic theory remained unchanged throughout history. (True/False)
false
Who proposed the idea that atoms are indivisible and indestructible?
a) Ernest Rutherford
b) The ancient Greeks c) John Dalton
b) The ancient Greeks
Who discovered the nucleus of an atom?
a) J.J. Thomson
b) Ernest Rutherford
c) The ancient Greeks
b) Ernest Rutherford
Which model of the atom proposed that electrons orbit the nucleus in fixed paths?
a) Plum pudding model
b) Bohr model
c) Thompson model
b) Bohr model
Who proposed the first modern atomic theory?
a) John Dalton
b) Niels Bohr
c) Ernest Rutherford
a) John Dalton
Which of the following is a characteristic of metals?
a) Brittle
b) Poor conductors of heat and electricity
c) Malleable and ductile
c) Malleable and ductile
Which element is a non-metal?
a) Sodium (Na)
b) Oxygen (O)
c) Iron (Fe)
b) Oxygen (O)
What state are most metals at room temperature?
a) Gas
b) Liquid
c) Solid
c) Solid
Which of the following is a property of non-metals?
a) Shiny appearance
b) High melting points
c) Brittle when solid
c) Brittle when solid
Metals are ductile. (True/False)
true
Non-metals are lustrous or shiny. (True/False)
false
Sodium (Na) is a non-metal.
(True/False)
false
Both metals and non-metals can conduct electricity.
(True/False)
false
Metals are usually good ________ of heat and electricity
conductors
Metals can be hammered or rolled into foils. A word for this property is ________ .
malleable
The majority of elements in the periodic table are ________.
metals
Explain the difference between metals and non-metals based on their physical properties.
Metals are typically shiny (lustrous), malleable, and ductile. They are good conductors of heat and electricity and have high melting and boiling points. Non-metals, on the other hand, are usually dull in appearance, brittle when solid, and poor conductors of heat and electricity. They have lower melting and boiling points compared to metals.
Provide an example of a metal and describe one of its uses.
Example: Iron is a metal commonly used in construction and manufacturing. It is used to make steel, which is essential for building structures, bridges, and machinery.
Describe a property of non-metals that makes them different from metals.
They are generally brittle when solid, unlike metals which are malleable and ductile.
they are not good conductors of heat
Describe where metals and non-metals can be found on the periodic table
Metals are to the left of the metal/non-metal border, non-metals are to the right of this border
Compare metalloids with metals and non-metals
Metalloids can have properties of both metals and non-metals. They are found around the metal/non-metal border on the periodic table.
Describe the structure of an ionic lattice and how it forms.
In an ionic lattice, positive and negative ions are held together by strong electrostatic forces of attraction. It forms when one or more electrons are transferred from one atom to another, resulting in the formation of positively charged cations and negatively charged anions.
Explain the difference between a covalent lattice and a molecule
A covalent lattice consists of atoms held together by covalent bonds arranged in a repeating three-dimensional pattern. Molecules, on the other hand, are discrete units consisting of atoms bonded together by covalent bonds.
Provide an example of a molecule and describe its structure.
Example: Water (H₂O) is a molecule consisting of two hydrogen atoms bonded to one oxygen atom. The atoms are held together by covalent bonds, and the molecule has a bent shape due to the arrangement of the atoms.
Molecules are made up of ________ atoms bonded together.
non-metal
Diamond is an example of a ________ lattice.
covalent
In an ionic lattice, ions are held together by ________ bonds.
ionic
Covalent bonds involve the transfer of electrons between atoms.
(True/False)
false
Molecules can exist as discrete units or as part of a larger lattice structure.
(True/False)
true
Covalent lattices are typically formed by metals and non-metals.
(True/False)
false
Ionic lattices are formed by the sharing of electrons between atoms.
(True/False)
false
Which of the following is a characteristic of molecules?
a) They have a fixed, repeating arrangement of atoms. b) They consist of ions arranged in a lattice structure.
c) They are held together by covalent bonds
c) They are held together by covalent bonds.
Covalent lattices are made up of:
a) Ions held together by ionic bonds.
b) Atoms held together by covalent bonds.
c) Metal atoms held together by metallic bonds.
b) Atoms held together by covalent bonds.
Which of the following substances is an example of an ionic lattice?
a) Carbon dioxide (CO₂)
b) Sodium chloride (NaCl)
c) Diamond (C)
b) Sodium chloride (NaCl)
What type of bonding forms an ionic lattice? a) Covalent bonding
b) Metallic bonding
c) Ionic bonding
c) Ionic bonding
