I need help with 1-7 ASAP

Use your periodic table to answer the following question.

Pavel [41]

Helium has only 2 electrons in it's valence shell

So, option D is your answer.

Hope this helps!

6 0

3 years ago

In each of the parts of this question, a nucleus undergoes a nuclear decay. Determine the resulting nucleus in each case.

MA_775_DIABLO [31]

A) Francium-223

In an alpha decay, a nucleus decay emitting an alpha particle, which corresponds to a nucleus of helium: so, it consists of 2 protons and 2 neutrons.

$X \rightarrow X' + \alpha$

This means that in the decay:

- The original nucleus loses 2 protons --> so its atomic number Z decreases by 2 units

- The original nucleus loses 2 nucleons (2 protons and 2 neutrons) --> so its mass number A decreases by 4 units

In this example, the original nucleus is Ac (Actinium), with

Z = 89

A = 227

After the decay, it must be

Z - 2 = 89 - 2 = 87

A - 4 = 227 - 4 = 223

We see from the periodict table, Z=87 corresponds to Francium (Fr), so the final nucleus will be francium-223 (the isotope of francium with 223 nucleons).

B) Polonium-211

In a beta-minus decay, a neutron in the nucleus turns into a proton, emitting a fast-moving electron (the beta particle) and an anti-neutrino.

$n \rightarrow p + e^- + \bar{\nu}$

Therefore, in this process:

- The original nucleus gains 1 protons, so its atomic number Z increases by 1 unit

- The original nucleus does not lose/gain nucleons, so its mass number A remains the same

In this example, the original nucleus is Bi (bismuth)-211, with

Z = 83

A = 211

So After the decay, it will be

Z + 1 = 83 + 1 = 84

A = 211

So, the nucleus will be Polonium (Z=84), isotope with 211 nucleons.

C) Neon-22

In a beta-plus decay, a proton in the nucleus turns into a neutron, emitting a fast-moving positron (the beta particle) and a neutrino.

$p \rightarrow n + e^+ +\nu$

Therefore, in this process:

- The original nucleus loses 1 protons, so its atomic number Z decreases by 1 unit

- The original nucleus does not lose/gain nucleons, so its mass number A remains the same

In this example, the original nucleus is Na (sodium)-22, with

Z = 11

A = 22

So After the decay, it will be

Z - 1 = 11 - 1 = 10

A = 22

So, the nucleus will be Neon (Z=10), isotope with 22 nucleons.

D) Technetium-98

In a gamma decay, an unstable nucleus emits a gamma ray:

$X' \rightarrow X + \gamma$

In this process, only energy is released (in the form of gamma ray), so there is no gain/loss of protons/neutrons in the process. This means that:

- The atomic number Z remains constant

- The mass number A remains constant

In this example, we have a nucleus of Tc (Technetium)-98, with

Z = 43

A = 98

These numbers will not change during the decay: this means that after the decay, we will still have a nucleus of Technetium-98.

8 0

4 years ago

The presence of foreign pottery in a well-dated Egyptian context shows that this type of pottery cannot be more recent than thos

Nutka1998 [239]

Answer:

TERMINUS ANTE QUEM

Explanation: Terminus ante quem is an Archeological an a Latin term used to describe the date before which an event or events took place,it is also used to show the date before which Archeological works have been deposited in a given area.

Example, a pottery dating to the 4th century AD found on a surface would give that pottery with a terminus ante quem of the 4thcentury AD.

This type of cross dating can either be TERMINUS ANTE QUEM OR TERMINUS POST QUEM.

3 0

3 years ago

Assuming that the relationship between spring compression and height is quadratic, how far will the ball go at the highest setti

adelina 88 [10]

Assuming that the relationship between spring compression and height is quadratic, 2.25m far will the ball go at the highest setting, compresses the spring 3 cm

<h3>How do you calculate a compression spring's solid height?</h3>

The solid height, h1, of an unground spring is (n+1)d, where n is the number of coils and d is the wire diameter (including platings and coating) in inches. The height, h2, of ground but not squared springs is (n-1)d. The solid height, h3, of ground and squared springs is (n-0.75)d

When a spring is compressed, the potential energy is stored in the mechanical bonds between atoms, which may be thought of as little springs. The spring as a whole cannot decompress until it breaks, but little portions may when they fall off. The majority of the stored energy is used to decompress each little component.

learn more about potential energy refer

brainly.com/question/14427111

#SPJ4

5 0

1 year ago

A ledge on a building is 18 m above the ground. A taut rope attached to a 4.0-kg can of paint sitting on the ledge passes up ove

True [87]

Answer:t=5.07 s

Explanation:

Given

height of Building h=18 m

mass of Paint can $m_1=4 kg$