Atomic Structure

Atoms of the same element in the same group have the same number of:

Which of the following is the correct symbol for Silver?

What is the maximum number of electrons that can be held in the third shell ($n=3$) for the first 20 elements?

Which of these elements is a non-metal that is a liquid at room temperature?

In an atom, where is nearly all of the mass located?

Which set of elements consists only of Noble Gases?

What is the mass number of an atom containing 6 protons, 8 neutrons, and 6 electrons?

Which element in Period 2 has the greatest difference between its $IE_{3}$ and $IE_{4}$?

What occurs when an electron moves from $n=1$ to $n=3$?

In the mass spectrum of bromine, which naturally exists as $^{79}Br$ and $^{81}Br$ in a $1:1$ ratio, how many peaks would be observed for the $Br_{2}^{+}$ ion?

An atom has a mass number of 32 and contains 16 neutrons. What is its atomic number?

Which particle is located in the nucleus and has a relative mass of 1?

How many protons are present in an atom of Calcium-40 ($^{40}_{20}Ca$)?

To find the number of neutrons in an atom, which mathematical operation is used?

An isotope of Bromine has an atomic number of 35. The flowchart below represents the composition of its nucleus. Based on the information provided, what is the value of $N$ (the number of neutrons) for this isotope?

If the mass number of an element is doubled but the atomic number stays the same, what has changed?

An atom has 8 protons and 10 neutrons. What is its mass number and atomic number?

In the ion $^{32}_{16}S^{2-}$, what are the counts of protons ($p$), neutrons ($n$), and electrons ($e$)?

An atom of element $K$ has 19 protons. An isotope of $K$ has 22 neutrons. What is the mass number of this isotope?

Element $Z$ has an atomic number of 53. One of its ions has 54 electrons and 74 neutrons. What is the mass number and the charge of this ion?

The total number of protons and neutrons in the nucleus of an atom is called the:

If an atom has the same number of protons and electrons, but a different number of neutrons than another atom of that element, it is a neutral:

Which of the following is an isotope of $^{12}_{6}C$?

An isotope of Cobalt-60 is often used in medicine. If Cobalt has an atomic number of 27, how many neutrons are in Cobalt-60?

Calculate the number of neutrons in an atom of $^{201}_{80}Hg$.

Which of these is a likely difference between the isotopes $^{20}Ne$ and $^{22}Ne$?

Why is the relative atomic mass of most elements not a whole number?

Silicon has three isotopes: $^{28}Si$ (92.2%), $^{29}Si$ (4.7%), and $^{30}Si$ (3.1%). Which of the following is the most likely value for its relative atomic mass?

Which isotope is used as a standard for the definition of the atomic mass unit (amu)?

In a sample of Copper ($A_r = 63.55$), the two isotopes are $^{63}Cu$ and $^{65}Cu$. Calculate the percentage of $^{63}Cu$ in the sample.

What is the name for the rows at the very bottom of the Periodic Table, separate from the main body?

How many protons are in an atom of Aluminum (Atomic number 13)?

Which of the following is a noble gas used in light bulbs and signs?

Which group contains elements that have 7 valence electrons?

Which of the following elements is a transition metal?

Across Period 2, from Lithium to Fluorine, what happens to the attraction between the nucleus and the valence electrons?

Which of the following describes an element that is likely to form a $3+$ ion?

An unknown metal $M$ forms a stable $M^{2+}$ ion, while an unknown non-metal $X$ forms a stable $X^{-}$ ion. If these two ions are isoelectronic (have the same electronic configuration), which of the following statements must be true regarding the neutral atoms and their ions?

Which statement best compares the atomic radius of Lithium ($Li$) and Beryllium ($Be$)?

Which of the following has the highest electron affinity (most energy released)?

If an atom has 8 protons, 8 neutrons, and 8 electrons, its mass number is:

What is the valency of Hydrogen ($Z=1$)?

In the atom, where are the neutrons located?

How many valence electrons does Neon ($Z=10$) have?

An atom of an element has an atomic number of $15$. The diagram shows the distribution of its electrons across different energy levels. Based on this structure, how many valence electrons does the atom possess, and what is its valency?

Which of these elements has a valency of 1?

What happens to the number of shells as you move down a group in the Periodic Table?

A neutral atom of an element $T$ has a mass number of 39, and the number of neutrons in its nucleus is one greater than the number of protons. Element $T$ reacts with Oxygen to form a stable ionic compound. Using the reasoning path provided in the flowchart, determine the electronic configuration of the most stable ion formed by element $T$ and the correct chemical formula of its resulting oxide.

What is the ratio of the number of electrons in the $K$, $L$, and $M$ shells of a neutral Chlorine atom?

An element $X$ has 12 protons. What is the valency of the element $Y$ which is just below $X$ in the same group of the Periodic Table?

As you go from Cesium ($Cs$) to Fluorine ($F$) diagonally across the Periodic Table, electronegativity:

Which of the following is the least electronegative non-metal in Period 2?

Which element has an electronegativity of approximately 3.0?

Which of these is a characteristic of a highly electronegative atom?

A section of the Periodic Table is shown in the diagram below, representing two adjacent groups and two adjacent periods. Based on the electronegativity values provided for the first three elements, what is the most probable value for the 'Unknown' element?

Given the electronegativity values $C=2.5$ and $O=3.5$, which atom in a Carbon Monoxide ($CO$) molecule will have a partial positive charge ($\delta+$)?

Which statement about the electronegativity of Halogens is true?

Elements $A$, $B$, and $C$ are positioned in the periodic table relative to each other as shown in the diagram. Based on the fundamental periodic trends of atomic structure and electronegativity, which of the following chemical bonds would be predicted to have the greatest dipole moment (highest bond polarity)?

Despite having a significantly higher nuclear charge ($Z = 35$), Bromine ($Br$) has an electronegativity value of $2.96$, which is relatively close to that of Sulfur ($S$, $\chi = 2.58$, $Z = 16$). Based on the provided diagram of their atomic structures, which statement best explains why the electronegativity does not increase as much as the nuclear charge would suggest?

Which pair of elements will form a bond with the MOST covalent character?

In the Periodic Table, elements with similar chemical properties are arranged in vertical columns, as shown in the example diagram. What is the scientific term for these columns?

Which of the following describes the trend in melting points for Group I metals as you go down the group?

When a Group I metal reacts with water, the resulting solution is:

Which subatomic particles are found in the nucleus of an atom?

Why do the atoms of Group VII elements become larger as you go down the group?

Which Group II element reacts most slowly with cold water?

Which statement about Group 0 elements is correct?

An unknown element $Z$ is in Group VII. It is a liquid at $25^\circ C$. If $Z$ is added to a solution of Sodium Iodide, what is the most likely result?

What is the correct chemical formula for the compound formed between Barium and Nitrogen?

Which Group I metal would you expect to have the highest melting point?

Why are transition metals called 'transition' elements?

Which transition metal is found in Vitamin B12?

Which rare earth metal is commonly used in battery electrodes for hybrid cars?

Most actinides are synthetic. What does 'synthetic' mean?

Transition metals are known for their ability to form ions with different charges, a property called 'variable oxidation states.' Based on the diagram showing the transition between two different iron ions, which of the following statements correctly describes the difference in their atomic structure?

Which transition metal is commonly used in rechargeable batteries (e.g., NiMH batteries)?

The colors of transition metal compounds are usually explained by the movement of electrons between:

In many transition metal complexes, the arrival of ligands (such as $H_{2}O$) causes the five $d$-orbitals to split into different energy levels. Based on the diagram provided, what is the primary mechanism that produces the specific colors seen in these metal ions?

Which of the following transition metals is a vital component of Vitamin B12?

The lanthanide contraction explains why which pair of elements has nearly identical atomic radii?

Which statement about noble gases is true?

Which element has 11 protons, 12 neutrons, and 11 electrons?

Most metals are in which state at room temperature?

How many electrons can the second shell of an atom hold?

An element has the electron configuration 2, 8, 8, 1. To which Group and Period does it belong?

Which of the following is a characteristic of metallic bonding?

Which of the following elements is a gas at room temperature and exists as monatomic atoms?

Explain why the melting point of Chlorine ($Cl_{2}$) is lower than that of Iodine ($I_{2}$)?

Which of the following statements about the Periodic Table's 'staircase' is correct?

A substance has a high melting point, is hard but brittle, and conducts electricity only when molten or in aqueous solution. What type of bonding is likely present?

The path followed by electrons around the nucleus is called:

How many electrons are in the outer shell of Sulfur ($Atomic\,Number = 16$)?

An atom has 13 protons and 14 neutrons. What is its electronic configuration?

Which group does an element with configuration $2, 8, 2$ belong to?

How many electrons does a neutral Beryllium atom ($Z=4$) have in its outer shell?

Which of these electronic configurations represents a metal in Period 3?

How many electrons are found in the valence shell of an atom of Neon?

Which atom has the largest number of electrons in its outermost occupied shell?

A cation with a $2+$ charge has the configuration 2, 8. What was the configuration of the neutral atom?

If an atom has the configuration 2, 8, 4, what is its total number of electrons and its identity?

What is the relative atomic mass of Bromine (Br)?

Carbon has an $A_r$ of 12.01. Why is it not exactly 12.00?

What is the $A_r$ of Phosphorus (P)?

Which group of the Periodic Table contains elements with the lowest relative atomic masses?

If the relative atomic mass is $A_r$, then the mass of one atom of an element in grams is calculated by:

Calculate the relative atomic mass of Silicon: $Si-28$ ($92.2\%$), $Si-29$ ($4.7\%$), $Si-30$ ($3.1\%$).

Rubidium has two isotopes, $^{85}Rb$ and $^{87}Rb$. If the $A_r$ is $85.47$, which isotope is more abundant?

Given the relative atomic masses: $H=1, O=16, S=32$. What is the relative formula mass of $H_2SO_4$?

Calculate the $A_r$ of an element with isotopes $X-24$ ($79\%$) and $X-26$ ($21\%$).

How many neutrons are in an atom of $^{13}C$, and how does this isotope affect the $A_r$ of Carbon ($12.01$)?

Which of the following is true for all Group 1 elements?

If an element $X$ is an alkali metal, what is the formula of its oxide?

Which gas is NOT involved in the reaction of Sodium with water?

The ionic bond formed by alkali metals usually involves:

In Group 1 (the Alkali Metals), several atomic and physical properties follow a consistent trend as the atomic number increases. Based on the diagram, which pair of properties both decrease as you move down the group?

Which Group 1 element is predicted to be the most reactive, although it is extremely rare and radioactive?

In the context of Atomic Structure, what is a 'valence electron'?

Which equation correctly represents the first ionization of Lithium?

In a flame test, if you observe a pale violet (lilac) color, which ion is most likely present and what does this indicate about the energy of the emitted photon compared to a red flame?

Which of the following best explains why the Alkali Metals are found in Nature only as compounds and never as pure elements?

Which of the following elements has 7 valence electrons?

In the Periodic Table, where are the Halogens located?

Which halogen has the smallest atomic radius?

What is the name of the $Cl^-$ ion?

A student is given an aqueous solution of an unknown halogen, $X_2$. They perform two displacement tests as shown in the flowchart below. Based on the observations, which halogen is $X_2$?

A student predicts that Tennessine (Element 117) will be a solid. What is the most likely reason for this prediction?

What is the correct order of the halogens in Group 7, starting from the top?

Identify the correct order of increasing atomic radius for the following species: $F, Cl, Cl^-$.

Which of the following best describes the color change when Chlorine water is added to a Potassium Bromide solution?

Which property decreases as you go down Group 7?