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2 years ago

Why are lanthanum and actinium at the bottom of the periodic table?

1 answer:

8 0

The periodic table is organized in a way in which trends with certain things such as ionization energy or atomic radius would "work out". It also have increasing atomic mass.

It's also organized to tell you the electron and proton of each element, least to greatest. (the atomic number) Example: Chlorine has 17 protons and 17 e-
(Left to right)
(Top to bottom)

Lanthanum and actinium play the role of being in the bottom because of their large atomic radius and having many protons/electrons.
They're also in the F block for electron configuration.

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When you throw a ball up in the air, it travels up and then stops instantaneously before falling back down. At the point where i

Gnoma [55]

Answer:

The ball stops instantaneously at the topmost point of the motion.

Explanation:

Assume we have thrown a ball up in the air. For that we have given a force on the ball and it acquires an initial velocity in the upward direction.

The forces that resist the motion of the ball in the upward direction are the force of gravity and air resistance. The ball will instantaneously come to rest when the velocity of the ball reduces to zero.

The two forces acting in the downward direction reduces its speed continuously and it becomes zero at the topmost point.

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3 years ago

Since astronauts in orbit are apparently weightless, a clever method of measuring their masses is needed to monitor their mass g

monitta

Answer:

55.56kg

Explanation:

Given:

F= 52N

a=0.936m/s²

Applyinc Newton's second law, that states: force is equal to mass times acceleration.

F = ma

m=F/a =>52 / 0.936

m=55.56kg

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3 years ago

Which of these actions will increase friction? Select three options. Scratching a surface to make it rougher polishing a surface

k0ka [10]

Answer:

scratching a surface to make it rougher

increasing the size of a flying object

adding extra weight to an object

Explanation:

5 0

2 years ago

Read 2 more answers

Can someone help me?!!!!!

ladessa [460]

Answer:

magnitude: 21.6; direction: 33.7 degrees

Explanation:

When we multiply a vector by a scalar, we have to multiply each component of the vector by the scalar number. In this case, we have

vector: (-3,-2)

Scalar: -6

so the vector multiplied by the scalar will have components

$(-3\cdot (-6), -2 \cdot (-6))=(18,12)$

The magnitude is given by Pythagorean's theorem:

$m=\sqrt{18^2+12^2}=21.6$

and the direction is given by the arctan of the ratio between the y-component and the x-component:

$\theta = tan^{-1} (\frac{12}{18})=33.7^{\circ}$

3 0

3 years ago

In this activity, you will research how scientists developed historical

Darya [45]

Answer: Bohr's model (1913)

Niels Bohr improved Rutherford's model. Using mathematical ideas, he showed that electrons occupy shells or energy levels around the nucleus. The Dalton model has changed over time because of the discovery of subatomic particles.

Bohr's model (1913)

Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.

John Dalton

The idea that everything is made of atoms was pioneered by John Dalton (1766-1844) in a book he published in 1808. He is sometimes called the "father" of atomic theory, but judging from this photo on the right "grandfather" might be a better term.

Explanation:

8 0

2 years ago