Question

isotope activity
for all elements, the number of neutrons can make the nucleus stable or unstable.
too few or too many n⁰ will make a nucleus unstable and the atom will undergo radioactive decay.
recall that mass number in the name of an isotope is p⁺ + n⁰.
make sure you are checking the periodic table and have the right element.
step 1: add p⁺ until you have the right element.
step 2: add n⁰ until the isotope mass is correct.
step 3: check stability.
only answer this for unstable

1. build lithium - 5. this isotope is stable / unstable . it has too few / too many n⁰.

build lithium - 6. this isotope is stable / unstable . it has too few / too many n⁰.
build lithium - 7. this isotope is stable / unstable . it has too few / too many n⁰.
build lithium - 8. this isotope is stable / unstable . it has too few / too many n⁰.

1. build oxygen - 14. this isotope is stable / unstable . it has too few / too many n⁰.

build oxygen - 15. this isotope is stable / unstable . it has too few / too many n⁰.
build oxygen - 16. this isotope is stable / unstable . it has too few / too many n⁰.
build oxygen - 17. this isotope is stable / unstable . it has too few / too many n⁰.
build oxygen - 18. this isotope is stable / unstable . it has too few / too many n⁰.
build oxygen - 19. this isotope is stable / unstable . it has too few / too many n⁰.
analysis
circle any answer that is true. there may be more than 1 correct answer.
adding this subatomic particle to an atom changes the mass. p⁺ n⁰ e -
adding this subatomic particle to an atom changes the element. p⁺ n⁰ e -
adding this subatomic particle to an atom changes the electric charge. p⁺ n⁰ e -
with remaining class time, play a few games. see who can get the highest scores.
game

Explanation:

Step1: Recall atomic structure facts

Protons ($P^+$) determine element identity, neutrons ($N^0$) contribute to mass, and electrons ($e^-$) determine electric - charge.

Step2: Analyze effect on mass

Adding neutrons ($N^0$) or protons ($P^+$) changes mass as mass number = number of protons+number of neutrons. So adding $P^+$ or $N^0$ changes mass.

Step3: Analyze effect on element

Only adding protons ($P^+$) changes the element as the number of protons defines the element.

Step4: Analyze effect on electric charge

Adding electrons ($e^-$) changes the electric charge. Adding a proton also changes the charge but for neutral atoms adding an electron directly affects the charge.

For the isotope stability part:

Lithium isotopes:

• Lithium - 5: Unstable, too few $N^0$. Lithium has atomic number (number of $P^+$) = 3. For Li - 5, number of $N^0=5 - 3=2$. Stable lithium isotopes have more neutrons.
• Lithium - 6: Stable, appropriate number of $N^0$. For Li - 6, number of $N^0 = 6 - 3=3$.
• Lithium - 7: Stable, appropriate number of $N^0$. For Li - 7, number of $N^0=7 - 3 = 4$.
• Lithium - 8: Unstable, too many $N^0$. For Li - 8, number of $N^0=8 - 3=5$.

Oxygen isotopes:

• Oxygen - 14: Unstable, too few $N^0$. Oxygen has atomic number (number of $P^+$)=8. For O - 14, number of $N^0=14 - 8 = 6$.
• Oxygen - 15: Unstable, too few $N^0$. For O - 15, number of $N^0=15 - 8=7$.
• Oxygen - 16: Stable, appropriate number of $N^0$. For O - 16, number of $N^0=16 - 8 = 8$.
• Oxygen - 17: Stable, appropriate number of $N^0$. For O - 17, number of $N^0=17 - 8=9$.
• Oxygen - 18: Stable, appropriate number of $N^0$. For O - 18, number of $N^0=18 - 8 = 10$.
• Oxygen - 19: Unstable, too many $N^0$. For O - 19, number of $N^0=19 - 8=11$.

Answer:

1.

• Lithium - 5: Unstable, too few $N^0$
• Lithium - 6: Stable
• Lithium - 7: Stable
• Lithium - 8: Unstable, too many $N^0$

2.

• Oxygen - 14: Unstable, too few $N^0$
• Oxygen - 15: Unstable, too few $N^0$
• Oxygen - 16: Stable
• Oxygen - 17: Stable
• Oxygen - 18: Stable
• Oxygen - 19: Unstable, too many $N^0$

Analysis:

• Adding this subatomic particle to an atom changes the mass: $P^+$, $N^0$
• Adding this subatomic particle to an atom changes the element: $P^+$
• Adding this subatomic particle to an atom changes the electric charge: $e^-$