The entire mass of an atom is concentrated in the center of an atom called:
The nucleus contains most of the atom's mass because it includes both protons and neutrons.
The mass of an atom is determined by:
The mass of an atom is primarily determined by the sum of protons and neutrons in the nucleus.
Atoms of the same element having different mass numbers are called:
Isotopes are atoms of the same element with different numbers of neutrons, resulting in different mass numbers.
A chemical formula shows:
A chemical formula indicates the number of atoms of each element in a compound.
An atom has atomic number 16 and mass number 32. The number of protons is:
The atomic number represents the number of protons, which is 16 in this case.
What is the charge of a proton?
A proton has a positive charge of +1.
What is the relative mass of a neutron?
The relative mass of a neutron is approximately 1 atomic mass unit.
Which subatomic particle is negatively charged?
An electron carries a negative charge.
What forms when an atom gains electrons?
When an atom gains electrons, it becomes negatively charged and is called an anion.
What forms when an atom loses electrons?
When an atom loses electrons, it becomes positively charged and is called a cation.
What is the charge of a neutron?
A neutron has no charge; it is electrically neutral.
Which part of the atom contains protons and neutrons?
The nucleus of an atom contains both protons and neutrons.
What is found in electron shells?
Electrons are found in electron shells or orbitals around the nucleus.
The number of protons in an atom corresponds to:
In a neutral atom, the number of protons is equal to the number of electrons.
What are the three subatomic particles in an atom?
An atom consists of protons, neutrons, and electrons.
Where is the nucleus located in an atom?
The nucleus is located at the center of an atom.
Which subatomic particles are found in the nucleus?
The nucleus contains protons and neutrons.
What is the charge on a neutron?
A neutron has no charge; it is neutral.
What is the charge and mass of a proton?
A proton has a charge of +1 and a mass of approximately 1 atomic mass unit.
What is the charge of an electron?
An electron has a negative charge.
Which of the following is true about the number of protons and electrons in a neutral atom?
In a neutral atom, the number of protons is equal to the number of electrons.
What are nucleons?
Nucleons refer to protons and neutrons in the nucleus of an atom.
In which part of the atom do electrons revolve?
Electrons revolve around the nucleus in orbits or electron shells.
What does the atomic number represent?
The atomic number represents the number of protons in an atom.
What is the symbol used for atomic number?
The symbol used for the atomic number is Z.
If a carbon atom has 6 protons, what is its atomic number?
The atomic number is equal to the number of protons, which is 6 for carbon.
Mass number is the sum of:
The mass number is the sum of protons and neutrons in the nucleus.
Which formula is used to calculate the number of neutrons in an atom?
The number of neutrons (N) can be calculated using the formula \( N = A - Z \), where \( A \) is the mass number and \( Z \) is the atomic number.
What is the mass number of a carbon atom with 6 protons and 6 neutrons?
The mass number is the sum of protons and neutrons, which is \( 6 + 6 = 12 \).
The atomic mass of an element is expressed in:
Atomic mass is expressed in atomic mass units (amu).
Which subatomic particle determines the identity of an element?
The number of protons determines the identity of an element.
Which statement about electrons is correct?
Electrons revolve in orbits or electron shells around the nucleus.
What is the total number of nucleons in a carbon atom with atomic number 6?
The total number of nucleons is the mass number, which is 12 for a carbon atom with 6 protons and 6 neutrons.
The periodic table arranges elements by?
The periodic table arranges elements by increasing atomic number.
What is a period in the periodic table?
A period in the periodic table is a horizontal row of elements.
What do elements in the same group have in common?
Elements in the same group have the same number of electrons in their outermost shell, which gives them similar chemical properties.
What does valency represent?
Valency represents the combining capacity or power of an atom to form chemical bonds.
What is the valency of sodium (Na)?
Sodium has 1 electron in its outermost shell, giving it a valency of 1.
Why does chlorine have valency 1?
Chlorine has a valency of 1 because it tends to gain 1 electron to complete its octet.
How many electrons can the L-shell hold?
The L-shell can hold a maximum of 8 electrons.
What is the formula used to find maximum electrons in a shell?
The formula to find the maximum number of electrons in a shell is \( 2n^2 \), where \( n \) is the shell number.
Which shell is closest to the nucleus?
The K-shell is the closest to the nucleus.
What is a cation?
A cation is a positively charged ion formed when an atom loses one or more electrons.
What is an anion?
An anion is a negatively charged ion formed when an atom gains one or more electrons.
What happens to the size of an atom when it becomes a cation?
When an atom becomes a cation, it loses electrons, reducing the electron-electron repulsion and causing the ion to be smaller than the original atom.
Which of these is a cation?
Na⁺ is a cation because it is a positively charged ion.
Which of these is an anion?
Cl⁻ is an anion because it is a negatively charged ion.
What is the formula for water?
The chemical formula for water is H₂O, indicating two hydrogen atoms and one oxygen atom.
What is the formula for sodium chloride?
The chemical formula for sodium chloride is NaCl, indicating one sodium atom and one chlorine atom.
Which of the following statements best defines isotopes?
Isotopes are atoms of the same element with the same atomic number but different mass numbers due to varying numbers of neutrons.
What is the number of neutrons in Carbon-14?
Carbon-14 has a mass number of 14 and an atomic number of 6, so the number of neutrons is \( 14 - 6 = 8 \).
Which of the following is an isotope of hydrogen?
Deuterium is an isotope of hydrogen with one proton and one neutron.
How many protons are present in Tritium?
Tritium is an isotope of hydrogen, and all hydrogen isotopes have 1 proton.
Which isotope is used for carbon dating?
Carbon-14 is used for carbon dating due to its half-life, which makes it suitable for dating archaeological artifacts.
Which isotope is used in the diagnosis of thyroid function?
Iodine-123 is commonly used in the diagnosis of thyroid function due to its gamma-emitting properties and relatively short half-life.
Copper-64 is primarily used in the treatment of:
Copper-64 is used in the treatment of Wilson’s disease, a genetic disorder in which copper accumulates in the body.
Which of the following isotopes is used to detect cancer and infections?
Gallium-67 is used in medical imaging to detect certain cancers and infections in the body.
What is the mass number of Deuterium?
Deuterium has one proton and one neutron, giving it a mass number of 2.
The atomic number of all carbon isotopes is:
All carbon isotopes have an atomic number of 6, which is the number of protons in a carbon atom.
What is the number of neutrons in Carbon-13?
Carbon-13 has a mass number of 13 and an atomic number of 6, so the number of neutrons is \( 13 - 6 = 7 \).
Which of these isotopes is used to study iron metabolism?
Iron-59 is used to study iron metabolism in the body due to its radioactive properties.
In agriculture, which isotope is used to study nitrogen efficiency in fertilizers?
Nitrogen-15 is used in agricultural studies to assess the efficiency of nitrogen use in fertilizers.
Cobalt-60 is mainly used in:
Cobalt-60 is widely used in cancer radiotherapy due to its gamma radiation, which can target and destroy cancer cells.
Which isotope helps determine pollutant accumulation in soil layers?
Lead-210 is used to study the accumulation of pollutants in soil layers due to its presence in the environment and measurable decay.
Which subatomic particle determines the atomic number?
The atomic number is determined by the number of protons in the nucleus of an atom.
How many neutrons are there in Carbon-12?
Carbon-12 has a mass number of 12 and an atomic number of 6, so the number of neutrons is \( 12 - 6 = 6 \).
What is a molecule?
A molecule consists of two or more atoms chemically bonded together.
Which of the following is a molecule made up of the same element?
O₂ is a diatomic molecule made up of two oxygen atoms from the same element.
Which of the following is a compound?
H₂O is a compound made up of hydrogen and oxygen atoms chemically bonded together.
Which compound is correctly matched with its formula?
The correct formula for sodium chloride is NaCl, representing one sodium and one chlorine atom.
What is the chemical formula of hydrochloric acid?
The chemical formula for hydrochloric acid is HCl, indicating one hydrogen and one chlorine atom.
What is represented by a chemical formula?
A chemical formula represents the types and numbers of atoms in a molecule.
What is the ratio of sodium to chlorine in NaCl?
The ratio of sodium to chlorine in NaCl is 1:1, as indicated by its chemical formula.
Which law states that a compound always contains the same elements in the same ratio?
The law of constant composition states that a given chemical compound always contains the same elements in the same ratio by mass.
What is the ratio of hydrogen to oxygen in water?
The ratio of hydrogen to oxygen in water (H₂O) is 2:1.
Which compound always has one carbon and two oxygen atoms?
Carbon dioxide (CO₂) always has one carbon atom and two oxygen atoms.
The chemical formula for calcium chloride is:
The chemical formula for calcium chloride is CaCl₂, indicating one calcium atom and two chlorine atoms.
What is the formula of magnesium oxide?
The formula of magnesium oxide is MgO, indicating one magnesium atom and one oxygen atom.